The Science of Periodization for Female Triathletes: A Practical Guide to Menstruation, Contraceptives, and Training Adjustments

Coach’s Opening: Starting with a Message Received in the Early Morning

A few years ago, a female athlete preparing for the Kenting 226 sent me a message six weeks before race day: “Coach, I completely couldn’t hit my target power on today’s long ride. A section that’s usually easy at 180 watts felt like climbing Wuling today. Am I getting worse?” I looked at her training log for that week—elevated heart rate, heavy perceived exertion, poor sleep quality—and then asked a question that male coaches used to be afraid to ask, but which is actually crucial: “Is your period due this week?”

She paused and replied, “Yeah, it’s due tomorrow. How did you know?”

I’m not psychic. It’s because after coaching female athletes for a long time, you realize that the menstrual cycle is a severely underestimated training variable. Over the past two decades, almost all sports science research has been conducted on men, and female athletes have long been trained as “smaller versions of men,” which is highly inaccurate. Athletes themselves also often mistake normal fluctuations caused by their cycle for “I’m in a slump” or “Am I overtraining?” and consequently make the wrong adjustments.

In this article, I want to clearly explain my fifteen years of coaching observations, combined with the actual strength of evidence in current sports science literature. First, I need to state an important premise: the science in this field is far more uncertain than online summaries suggest. You’ll see definitive claims on Instagram like “train intensity during the follicular phase, train aerobic during the luteal phase,” but rigorous systematic reviews tell us it’s not that simple. I’ll be as honest as possible about what has evidence, what is merely reasonable inference, and what actually has very weak evidence.

Foundational Concepts: What Actually Happens During the Menstrual Cycle

Let’s start with the physiology. A standard menstrual cycle is about 28 days (the normal range is roughly 21 to 35 days), and we can roughly divide it into several phases. Understanding how hormones fluctuate is key to knowing why the body responds differently.

The Two Main Players: Estrogen and Progesterone

The entire cycle is driven by two ovarian hormones:

• Estrogen (Estradiol): Plays a role in “synthesis and repair,” related to bone health, muscle repair, ligament properties, and even a metabolic preference for burning fat.
• Progesterone: Rises after ovulation and is associated with increased basal body temperature, altered thermoregulation, water retention, and for some, mood and sleep changes.

The absolute concentrations and relative ratios of these two hormones differ greatly across cycle phases, and this is the root of all physiological changes.

A Quick Physiological Overview of the Four Cycle Phases

Phase	Approximate Days	Hormonal Characteristics	Common Subjective Feelings
Menstrual (Early Follicular)	Days 1–5	Both estrogen and progesterone are low	Cramping, fatigue, and iron loss possible in the first 1–2 days; but many feel lighter after day 3
Follicular (Late Follicular)	Days 6–13	Estrogen gradually rises	Many athletes report feeling their best, recovering quickly, and wanting to push hard
Ovulation	Around Day 14	Estrogen peaks then drops sharply; LH surges	Slight rise in body temperature; some research looks at changes in ligament laxity
Luteal	Days 15–28	Progesterone dominant, estrogen secondary	Basal body temperature rises about 0.3–0.5°C, possible water retention, PMS in the late phase

Please note the “Common Subjective Feelings” column—I use words like “common,” “many,” and “possible” because individual variation is enormous. I’ve coached athletes who set PBs during the luteal phase, and others who are completely flat on day one of their period. The cycle is a framework, not a verdict.

One Point Especially Important for Triathlon: Thermoregulation

During the luteal phase, rising progesterone increases basal body temperature by about 0.3 to 0.5 degrees Celsius, and the body’s “threshold” for initiating sweating and heat dissipation is delayed. For those of us living in Taiwan, often racing in hot, humid summer conditions, this is very practical.

When I’m preparing athletes in July and August, if an athlete is in the luteal phase and faces an afternoon run in Taiwan’s 32°C heat with 80% humidity, her perceived heat stress will be heavier than usual. This isn’t her getting weaker; it’s a change in the physiological background of thermoregulation. In such cases, I proactively adjust hydration and electrolyte strategies to be more aggressive and lower pace expectations, rather than forcing her to hold the original pace.

Strength of Evidence: Please Calm Down, Don’t Be Fooled by Online Summaries

This is the most important section of the entire article, and I want you to read it carefully.

A popular “periodized training” theory is widespread online: during the follicular phase, when estrogen is high, it’s suitable for high-intensity and strength training; during the luteal phase, you should do low-intensity aerobic work and rest more. It sounds scientific and appealing. But when I read genuinely rigorous systematic reviews, I find the evidence is far from that strong.

What the Systematic Reviews Say

A critical systematic review on “elite female athletes” (Frontiers in Physiology, 2021), after reviewing a large body of research, concluded that different performance parameters may be affected during the cycle, but the direction and magnitude of these effects are inconsistent and inconclusive. The researchers explicitly called for more long-term, prospective tracking studies before truly individualized recommendations can be made. In other words, current science is insufficient to support the strong claim that “following a cycle-based training plan will make you stronger.”

Another systematic review and meta-analysis on maximal strength also showed that most studies did not find consistent, significant differences in endurance, power, or strength performance across menstrual cycle phases.

The key point I want you to remember is: the group average effect is small, often even non-significant; but individual-level differences can be large. These two facts are not contradictory. The practical implication is—rather than applying a generic online template, honestly track your own responses.

Why Is the Evidence So Messy?

As a coach, I think it’s important to help you understand why research in this area is so difficult:

1. Accurate phase determination is hard: Many early studies only used “first day of last period” to calculate, without blood tests to confirm ovulation, resulting in athletes being misclassified into the wrong phase, making the data messy.
2. Sample sizes are often small: Strict recruitment criteria (no contraceptives, regular cycles) mean studies often have only a dozen or so participants.
3. Individual differences get averaged away: Averaging “people who get stronger in the luteal phase” with “people who get weaker in the luteal phase” leads to the conclusion of “no difference,” but this masks individual real responses.

So my position is clear: Treat the cycle as a personal variable to monitor, not a training template to copy.

Contraceptives: Another Big Question That Comes Up Often

Many female athletes use oral contraceptives for contraception, cycle regulation, or to improve menstrual pain and PMS, and naturally ask: “Coach, will taking the pill affect my performance?”

What Contraceptives Do

Oral contraceptives are a “double agent”: on one hand, they suppress your body’s own production of estradiol and progesterone; on the other, they provide exogenous estrogen and synthetic progestin on pill-taking days. So the hormonal environment for pill users is clearly different from women with natural cycles, and it’s relatively stable during the active pill days, unlike the dramatic fluctuations of a natural cycle.

Current Strength of Evidence

A systematic review and meta-analysis published in Sports Medicine (Elliott-Sale et al.) reached a conclusion worth citing: compared to the natural menstrual cycle, oral contraceptive use may cause a slight decrease in exercise performance, but this group-level effect is “most likely trivial.” Therefore, the researchers concluded that existing evidence is insufficient to provide general recommendations for or against contraceptive use.

They also emphasized that results vary greatly between individual studies, so the most practical approach is an individualized one—some athletes are affected, some not at all; the key is observing your own response to a specific medication.

This aligns perfectly with my coaching experience. I’ve coached athletes on the pill who felt no difference and continued to improve; I’ve also coached athletes who, after switching medications, felt noticeably more breathless on long efforts and recovered more slowly. There is no one-size-fits-all answer.

Three Things Coaches Should Remind Athletes

• This is a medical decision, not a training decision: Whether to use contraceptives, and which one, should always be evaluated by a gynecologist first; training is a secondary consideration. I never tell athletes to adjust their medication for performance.
• Record before and after switching medications: If a doctor recommends a change, keep a training log (power, heart rate, perceived exertion, sleep) for a period before and after the switch, so you can assess the impact.
• Don’t treat contraceptives as a sports supplement: They are not a tool for enhancing performance. Be very cautious of any claim that treats them as a “performance hack.”

Practical Methods: How to Track Effectively

Now that we’ve covered the science, let’s talk about what you can do today. Since the evidence tells us “individual response matters most,” tracking is the core of the entire system.

The Minimum Viable Tracking System

You don’t need to make it complicated from the start. I usually ask new athletes to start with a “three-column tracking method,” recording for at least 2 to 3 complete cycles:

1. Cycle Day: Mark the first day of your period as Day 1.
2. Objective Data: Key training data for the day—for example, heart rate at a fixed intensity, morning resting heart rate, or HRV (heart rate variability) if you measure it.
3. Subjective Feelings: Rate “leg feel,” “fatigue,” and “sleep quality” on a 1–10 scale, plus a free notes column (cramps, bloating, mood, digestion).

After three cycles, you’ll likely see your own patterns. This is more accurate than any online template.

Sample Tracking Table

Date	Cycle Day	Morning Resting HR (bpm)	Fixed Intensity RPE (1–10)	Sleep (1–10)	Notes
7/1	D1	54	7 (heavy)	5	Day 1 of period, cramps, reduced afternoon run
7/4	D4	51	4 (easy)	7	Recovered, leg feel is back
7/9	D9	49	3 (great)	8	Late follicular, intervals felt smooth, best RPE
7/20	D20	55	6	6	Luteal phase, afternoon run in high humidity felt especially hot, increased fluids
7/26	D26	57	7	5	PMS, bloating, low mood, workout changed to technique/low intensity

This is just a sample scenario; the numbers are for demonstration purposes, not for you to copy. The point is to build the habit of recording so your own body can speak.

Advanced: HRV and Morning Heart Rate

If you already track HRV or morning resting heart rate with a sports watch, you can overlay it with your cycle. Some athletes see a systematic increase of a few bpm in morning heart rate during the luteal phase or before their period. If HRV also drops simultaneously, that’s your body telling you “don’t push high intensity today.” But remember—HRV is heavily influenced by sleep, alcohol, stress, and caffeine. Don’t treat a single day’s number as gospel; look at trends.

Turning Tracking into Adjustments: An Example of Flexible Periodization

Many people ask whether they should “schedule workouts according to their cycle.” My answer is: First track, find your patterns, then talk about fine-tuning—and it’s fine-tuning, not major overhauls. Because the scientific evidence does not support rigid, large-scale scheduling.

Here’s a demonstration of a “flexible framework.” Treat it as a starting point, not a command:

Cycle Phase	Training Tendency (Flexible, Not a Hard Rule)	Triathlon Practical Example	Reminder for Coaches/Athletes
1–2 days before menstruation	Reduce volume flexibly based on cramp severity	Move the week’s high-intensity intervals back 1–2 days; do low-intensity riding or swim technique	Severe cramps mean rest day—no guilt
Late follicular (often feels best)	If you’re someone who feels great in this phase, schedule key workouts	Schedule VO2max intervals, tempo runs, or FTP tests	Only schedule if you “feel good”; don’t force it to fit a template
Around ovulation	Train normally, pay attention to joints	Normal training; if you’re prone to knee discomfort, do extra warm-up for technical movements	Research on ligament laxity is still inconsistent; don’t over-worry
Luteal phase	Be more cautious in hot environments; reduce volume if PMS is significant	In Taiwan’s summer, add fluids for afternoon runs and lower pace expectations	Thermoregulation background changes; heat stress is amplified

Let me emphasize again: if you’re in the luteal phase today but feel great and want to do intervals, then go do them. Your body’s immediate feedback always takes priority over this table. This table is a “default tendency when you have no clear signal,” not an iron law.

Sample One-Week Flexible Schedule (Standard Distance Race Prep)

Some athletes say: “Coach, I understand the principles, but can you just show me what an actual week looks like?” Okay, here’s an example for an intermediate athlete preparing for a 51.5 standard distance race, training about 8–10 hours per week. This is a “late follicular week” (usually the week athletes feel best). Please note this is a demonstration; the actual plan should be customized based on your tracking data:

Day	Session	Example Content	Purpose & Notes
Mon	Rest / Recovery	Complete rest or 30 min easy swim	Fixed recovery day on Monday, get enough sleep
Tue	Run (Key)	After warm-up, 5×1000m intervals with 2 min easy jog between	Late follicular feels good; schedule VO2max stimulus here
Wed	Bike (Aerobic)	90 min Zone 2 steady ride, HR below 70% of max	Build aerobic base; riverside bike path is great
Thu	Swim (Technique + Intervals)	After warm-up, 8×100m at steady pace, focus on stroke technique	Technique day, moderate intensity
Fri	Bike (Key)	After warm-up, 3×10 min at FTP intensity, 5 min easy between	Second high-intensity session of the week; can include a power test
Sat	Long Ride + Run (Brick)	2.5 hr bike followed by 20 min run at race pace	Simulate transitions; most critical session of the weekend
Sun	Long Run	75–90 min easy long run	Aerobic endurance, conversational pace

If the same athlete happens to be in the pre-menstrual or late luteal phase this week and feels noticeably heavy, I wouldn’t rigidly apply the table above. I’d downgrade one of the two high-intensity sessions on Tuesday and Friday to tempo or aerobic work, and possibly shorten the run segment of Saturday’s brick. The same training structure, flexing according to body signals—this is what “flexible periodization” really looks like in practice, not mechanically cutting volume every month.

Practical Considerations for Cycle and Taiwan’s Race Calendar

Taiwan’s triathlon season is concentrated, with many standard and long-distance races from late spring to autumn, and summers are particularly hot and humid. If your target race date is set and your cycle is fairly regular, you can calculate backward to estimate which phase race day will likely fall in.

But I have to be honest: Don’t intervene with your body just to “schedule a race in an ideal phase.” As discussed, the science doesn’t support the strong claim that “a certain phase guarantees better performance,” and using medication to shift your cycle is a medical decision. A more practical approach is—if you expect the race to fall in a phase where you personally tend to feel weaker, then put extra effort into nutrition, cooling, pace expectations, and mental preparation. Control the controllable variables, rather than gambling on a hormonal advantage with weak evidence.

Nutrition and Fueling: Practical Fine-Tuning Across Cycle Phases

Many athletes overlook this section, but it actually has more immediate practical value than “scheduling workouts by cycle phase.”

Iron: The Hidden Landmine for Female Endurance Athletes

I mentioned iron earlier; let’s expand on it. Women are more prone to iron deficiency than men due to monthly blood loss, and endurance training itself (especially the impact of running) also increases iron loss. Typical signs of iron deficiency are “feeling tired no matter how much you sleep, inexplicably high heart rate at the same intensity, and especially breathless on climbs”—many athletes mistake this for “not training hard enough” and increase volume, making things worse.

Practically, I remind athletes: include red meat, dark leafy greens (spinach, sweet potato leaves), legumes, and eggs in your diet; pair them with vitamin C-rich foods (like guava or citrus) to aid absorption; and try to separate tea and coffee from meals, as tannins inhibit iron absorption. But whether to get blood tests or take iron supplements must be decided by a doctor—self-supplementing with excessive iron is harmful, and that’s a red line you cannot cross.

Energy Availability: The More Important Foundation Than Periodization

Let me repeat the concept I care most about: eating enough is the prerequisite for everything. Triathlon training volume is high; if you’re in a long-term calorie and carbohydrate deficit, your body will suppress “non-essential” functions, including reproductive endocrinology, causing irregular or even absent periods (this is the core of RED-S, Relative Energy Deficiency in Sport). This doesn’t just affect performance; it harms bone health and increases the risk of stress fractures.

Taiwan’s eating-out environment is actually quite friendly for meeting energy needs. For post-workout recovery, convenience stores have you covered: an onigiri or sweet potato for carbs, a tea egg or a carton of unsweetened soy milk for protein—convenient and affordable. Don’t deliberately undereat after long sessions to control weight—for endurance athletes, the damage of under-eating far outweighs eating a bit more.

Hydration and Electrolytes in the Luteal Phase

Some athletes feel bloated or notice different thirst sensations during the luteal phase. Combined with the altered thermoregulation threshold mentioned earlier, I ask athletes to be more proactive with electrolyte intake during long summer sessions in Taiwan, rather than just drinking plain water. Sweating heavily and only replacing with plain water can actually lead to electrolyte imbalance. The exact amount varies by individual; the principle is to “follow sweat rate and perceived thirst,” taking small, regular sips of sodium-containing sports drinks or electrolytes during long sessions.

Three Common Mistakes and Their Fixes

Over years of coaching, I’ve seen athletes (and some coaches) repeatedly fall into these traps:

Mistake 1: Misinterpreting Cycle Fluctuations as “Getting Worse” or “Overtraining”

Scenario: An athlete can’t hit power before her period, heart rate is elevated, and she starts to panic, thinking “Am I overtraining?” She then randomly adds rest days or changes her training plan, disrupting the entire week’s rhythm.

Fix: First, check the cycle day. If it’s the predictable late luteal or pre-menstrual phase, this is likely normal fluctuation, not a danger signal. This is exactly why tracking is so important—with 2–3 cycles of data, you can tell at a glance whether “this is my monthly pattern” or “something is genuinely wrong this time.”

Mistake 2: Believing Online Summaries and Rigidly Applying Templates

Scenario: Seeing “train less during the luteal phase,” an athlete drastically cuts training volume every month during the luteal phase, even though she’s someone who feels no difference in that phase, needlessly losing two weeks of training stimulus.

Fix: The evidence doesn’t support generic templates. Make decisions based on your own tracking data, not someone else’s rules.

Mistake 3: Ignoring the Two More Critical Foundations: Energy and Iron

Scenario: Spending lots of energy agonizing over “should I schedule workouts by my cycle,” while chronically under-eating and training hard, leading to increasingly irregular or absent periods, which is mistaken for “a normal sign that training is working.”

Fix: This is the one I worry about most. Irregular or absent periods in female endurance athletes are often a warning sign of inadequate energy intake (Relative Energy Deficiency in Sport, RED-S), not a badge of honor. Long-term energy deficiency harms bone health (increasing stress fracture risk), endocrine function, and long-term performance. Rather than obsessing over periodization details, first ensure:

• Eat enough: Triathlon training volume is high; calories and carbohydrates must keep up. Avoid long-term deficits. Taiwan’s convenience stores make it easy—sweet potatoes, tea eggs, onigiri, and unsweetened soy milk are all great grab-and-go options. Make “eating enough” your top priority.
• Watch your iron: Women lose iron monthly through menstruation, and endurance athletes are prone to deficiency. Iron deficiency directly makes you “tired no matter how you train, with inexplicably high heart rate.” Red meat, dark leafy greens, and legumes are sources, but whether to get blood tests or supplement should be left to a doctor—don’t self-supplement with iron (excess is harmful).

If your period becomes irregular or disappears, see a doctor first, not your coach. This is a health issue that outranks any training consideration.

Strength Training and Injury Risk: A Frequently Discussed but Still Weakly Supported Angle

Most triathletes incorporate strength training, so I’m often asked: “Coach, since estrogen is high in the follicular phase and muscle protein synthesis is better, should strength sessions be scheduled then?” Others worry that ligaments are looser around ovulation, increasing injury risk.

I must be honest: the current evidence for both questions is not as definitive as the internet suggests.

Regarding strength, the systematic review mentioned earlier showed that most studies did not find consistent, significant differences in maximal strength across cycle phases. So the claim that “training is definitely more effective in the follicular phase” has weak evidence. My approach is: if your tracking shows you feel particularly strong and recover quickly during a certain phase, then by all means schedule key strength sessions then—that’s reasonable individualization. But you don’t need to rigidly lock strength training into two specific weeks every month based on a weak general rule.

Regarding injury risk, you often hear claims like “estrogen affects ligament laxity around ovulation, increasing ACL injury risk.” This topic is discussed more in team ball sports (which involve lots of sudden stops and direction changes). For triathlon, which is primarily linear and cyclical, the direct relevance is less clear, and research conclusions are inconsistent. My advice is simple: regardless of the phase, warming up properly, progressing gradually, and executing technical movements correctly is always more practical than worrying about being “especially injury-prone” on a particular day. Excessive worry can make athletes hesitant on days when they should be training normally.

Psychology and Emotion: Don’t Overlook This Aspect

Finally, let me add an aspect often overlooked by data-driven coaches: emotion and psychology. Some athletes experience noticeably low mood, irritability, and decreased motivation before their period (PMS), and their “feel” for training worsens. This isn’t a lack of willpower; it’s a real physiological background at play.

When coaching, I address this openly: if you know you tend to feel down in the days before your period, then proactively schedule those days’ workouts to be more friendly—include sessions you enjoy and find rewarding (like a swim technique session you’re good at, or an easy group ride with friends), rather than forcing a high-intensity test that will leave you frustrated. Taking care of the psychological experience of training leads to better long-term consistency. This is one of the hidden benefits of “knowing your cycle.”

Actionable Advice for Athletes at Different Levels

Beginners / Those Just Starting to Track

• At this stage, don’t overthink periodization. First, solidify the three foundations of “consistent training + eating enough + sleeping well.” The benefits far outweigh obsessing over your cycle.
• Start with the simplest “three-column tracking” and record for two to three months, just to get to know your body’s rhythm.
• On days with severe cramps, allow yourself to rest or do easy activities without guilt.

Intermediate / Those with Established Periodized Training

• Overlay your cycle data onto your existing training logs (power, heart rate, HRV) to identify your patterns.
• Start making flexible fine-tunings: during phases when you typically feel best, prioritize key workouts (tests, key intervals); during phases when you typically feel worse, leave room for flexible volume reduction.
• When preparing for Taiwan’s hot, humid summer races (like summer triathlons), pay special attention to hydration and cooling during luteal phase runs.

Elite / Those Preparing for Qualifying Races

• You and your coach should formally integrate cycle tracking into your training monitoring system, and collaborate with your sports medicine team and gynecologist.
• If key race scheduling has flexibility, you can reference your personal historical data—but recognize the limited strength of the scientific evidence and avoid over-promising “definitely better.”
• Be especially vigilant about RED-S: energy availability under high training volume is the foundation of your long-term performance and bone health.

Frequently Asked Questions (FAQ)

Q: Can I use contraceptives to “shift” my period for a race?
A: Clinically, some people do this, but it’s a medical decision that must be evaluated by a gynecologist. From a performance standpoint, the evidence doesn’t support that doing so will definitely make you faster; from a health standpoint, you definitely shouldn’t do it on your own. If you’re considering it, consult a doctor first.

Q: Can I train at high intensity during my period?
A: Yes. Menstruation itself is not a contraindication. Many athletes actually feel good after day 3 of their period. The only thing to adapt to is the severity of cramps in the first 1–2 days—if it hurts, reduce volume; if it doesn’t, train as usual. Listen to your body.

Q: My cycle is irregular. Does that mean I can’t track?
A: Irregularity itself is an important signal worth having a doctor evaluate to rule out issues like RED-S or PCOS. Until health concerns are clarified, periodized training should take a back seat.

Q: If I’m on contraceptives, do I still need to track?
A: Yes, but the focus of tracking is different. You can record your perceived exertion and data around the pill cycle (active pill days vs. placebo/off days) to see if you have any response. Most research shows performance is relatively stable during active pill use, but individual differences still exist.

Q: I see apps that can mark my cycle and automatically give training advice. Are they useful?
A: The features for marking your cycle, recording data, and viewing trends are very useful, and I encourage that. But if an app directly tells you to “train less today” just based on “what day you’re on,” be skeptical—that’s often the same evidence-poor generic template discussed earlier. Apps are great recording tools, but decisions should still come back to your own perceived exertion and objective data. Don’t treat algorithmic suggestions as medical advice.

Q: So, is periodized training worth doing? Give me a one-sentence conclusion.
A: It’s worth “tracking,” but be cautious about “copying templates.” Spending time understanding your own cycle response has almost no downside; but rigidly applying rigid online templates to yourself may cause you to needlessly lose training stimulus. Tracking is an investment; blindly following templates is a gamble.

Q: Are there any problems with swimming during my period?
A: With appropriate menstrual products (like tampons or a menstrual cup), there are no specific physiological contraindications to swimming during your period. Whether to swim mainly depends on your own comfort and hygiene considerations. If in doubt, ask your doctor; there’s no need to interrupt your entire week of swim training.

Conclusion: Treat Your Body as a Teammate, Not an Opponent

After fifteen years of coaching female triathletes, the most important thing I want to convey is: The menstrual cycle is not your enemy, nor is it a reason to blame yourself for “being weak today.” It’s a set of signals worth getting to know.

The honest answer from science is: the group-level effect of the cycle on performance is actually small, and the evidence isn’t strong; the impact of contraceptives is mostly minimal; what’s truly valuable is getting to know your unique response patterns through long-term tracking, and then making flexible, practical fine-tunings—rather than copying someone else’s template, or resorting to medication or under-eating for the sake of performance.

Back to the athlete preparing for the Kenting 226 from the beginning. We didn’t drastically change her training plan. We just moved that week’s key long session back by three days to avoid the two heaviest days before her period, and made sure her iron and calorie intake were sufficient. On race day, she finished successfully and even set a new PB. The changes were small, but because we understood her body, every step was in the right place.

That is the most practical gift cycle science can give female triathletes.

---

This article is for educational purposes and cannot replace individual assessment by a physician, physical therapist, or nutritionist. All physiological and nutritional values mentioned are general ranges, and individual variation is enormous. If you experience irregular periods, amenorrhea, severe menstrual pain, suspected iron deficiency or energy deficiency, or are considering using or adjusting contraceptives, please consult a gynecologist or sports medicine professional first and make decisions based on your individual situation.

References

• The Effects of Menstrual Cycle Phase on Elite Athlete Performance: A Critical and Systematic Review (Frontiers in Physiology): https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.654585/full
• The Effects of Oral Contraceptives on Exercise Performance in Women: A Systematic Review and Meta-analysis (Sports Medicine): https://link.springer.com/article/10.1007/s40279-020-01317-5
• The Influence of Menstrual Cycle Phases on Maximal Strength Performance: A Systematic Review with Meta-Analysis (PMC): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10818650/

Related Reading

• Menstrual Cycle and Training Arrangement: Physiological Characteristics of Each Phase and Workout Adjustment Approaches (Highly Individual, Not an Iron Law)
• Adjusting Training for the Menstrual Cycle in Standard Distance Female Triathletes: Optimizing Workouts by Physiological Phase
• Special Nutritional Needs of Female Athletes: A Complete Coach’s Guide to the Menstrual Cycle, Iron and Calcium, and Energy Availability
• Training Differences for Female Cyclists: How the Hormonal Cycle Affects Athletic Performance