A Complete Guide to Garmin Training Readiness and Wahoo Training Load Metrics

Modern cycling computers and sports watches are full of various “training suggestion” metrics—Garmin tells you today’s Training Readiness is 42 (low), Wahoo shows your training load is “too high.” But what’s the logic behind these numbers? How much should we trust them?

The Garmin Training Ecosystem

Training Readiness

Training Readiness is a comprehensive metric Garmin introduced in 2022, presented on a 0-100 scale to indicate how ready you are to train on a given day.

Input factors (weighted from highest to lowest):

1. Sleep Quality and Duration (~30% weight)

   • Sleep tracking data from the watch
   • Includes proportions of deep, REM, and light sleep
   • Sleep duration compared against your personal baseline

2. Recovery Status / HRV Status (~25% weight)

   • Based on heart rate variability (HRV) during sleep
   • Compared against your 7-day rolling average and 90-day baseline
   • A drop in HRV typically reflects accumulated fatigue or stress

3. Acute Training Load (~20% weight)

   • Training load from the past 7 days (similar to ATL)
   • Considers workout type and intensity distribution

4. Training History (~15% weight)

   • Long-term training load trends (similar to CTL)
   • Rate of change in load

5. Stress Index (~10% weight)

   • All-day stress monitoring
   • Autonomic nervous system assessment based on HRV

Score interpretation:

Score Range	Status	Recommendation
80-100	Optimal	Suitable for high-intensity training or racing
60-79	Good	Can execute planned training
40-59	Moderate	Consider reducing intensity
20-39	Low	Recovery training or rest recommended
0-19	Very Low	Rest strongly recommended

Body Battery

Body Battery is another recovery metric from Garmin, presented as an energy value from 0-100 that changes in real time.

How it works:

• Based on Firstbeat Analytics algorithms
• Integrates heart rate, HRV, stress, and activity levels
• Similar to a phone battery: recharges during sleep, drains with activity
• High-stress events (like meetings) also drain energy

Differences from Training Readiness:

• Body Battery is a “real-time” metric that changes constantly
• Training Readiness is a “daily” metric, updated once in the morning
• Body Battery is better for judging your status “right now”
• Training Readiness is better for planning “today’s training”

Training Status

Training Status uses seven states to describe your training trends:

1. Peaking
The ideal pre-race taper state—load decreases while fitness remains high.

2. Productive
Training load is appropriate and fitness is continuously improving.

3. Maintaining
Load is sufficient to maintain current fitness levels.

4. Recovery
Load is low and the body is recovering.

5. Unproductive
Load is high but fitness isn’t improving—this could be insufficient recovery or a training structure problem.

6. Detraining
Load has been consistently low and fitness is starting to decline.

7. Overreaching
Load is too high with insufficient recovery—a warning sign.

The Wahoo SYSTM Training Load System

Wahoo’s methodology differs fundamentally from Garmin’s. Wahoo ELEMNT computers paired with the SYSTM training platform use the “4DP” (4-Dimensional Power) concept.

4DP Four-Dimensional Power

Unlike the traditional approach that only looks at FTP, 4DP measures four power dimensions:

1. NM (Neuromuscular Power): 5-second peak power
2. AC (Anaerobic Capacity): 1-minute power
3. MAP (Maximal Aerobic Power): 5-minute power
4. FTP: 20-minute power (adjusted)

Training Load Tracking

Wahoo’s training load metrics include:

Training Stress Score (similar to TSS):

• Calculated based on your 4DP profile, more precise than traditional TSS
• Tracks training stress separately across the four dimensions
• For example: a sprint workout creates high stress in the NM dimension but lower stress in the FTP dimension

Load Status Indicators:

• Uses a color system: green (appropriate), yellow (caution), red (too high)
• Displays load status for each of the four dimensions separately
• Can identify which energy system is being over-trained or under-trained

Practical Application: A One-Week Training Decision Example

Using the example of a Taiwanese cyclist using a Garmin 955 + Wahoo KICKR:

Monday Morning

• Training Readiness: 72 (Good)
• Body Battery: 85 (High)
• Wahoo Load: Green (appropriate across all dimensions)
• Decision: Execute the planned Sweet Spot intervals as scheduled

Wednesday Morning

• Training Readiness: 48 (Moderate)
• Body Battery: 55 (Moderate)
• Wahoo Load: NM/AC Yellow (did sprint training the day before)
• Decision: Switch to a Zone 2 recovery ride. Or, if the legs feel good, do the planned FTP interval workout (since NM/AC fatigue doesn’t affect FTP training)

Friday Morning

• Training Readiness: 38 (Low)
• Body Battery: 40 (Low)
• HRV Status: Below Baseline
• Decision: Take complete rest or do a 30-minute very low-intensity recovery ride

Saturday Morning (planned long ride day)

• Training Readiness: 65 (Good)
• Body Battery: 80 (High)
• Decision: Execute the long ride plan. You can arrange a 3-4 hour group ride at Yangmingshan or along the North Coast

Limitations of These Metrics

1. Optical Sensor Limitations

Wrist-based optical heart rate monitors have reduced accuracy in the following situations:

• Darker skin tones or tattoos on the wrist
• Watch band too loose
• Cold weather (vasoconstriction)
• Wrist movement during high-intensity exercise

Solution: Use a chest strap heart rate monitor, at least for important workouts

2. HRV Measurement Variability

Sleep HRV is affected by the following non-training factors:

• Alcohol consumption (significantly lowers HRV)
• Timing of caffeine intake
• Screen use before bed
• Room temperature
• Digestive state (dinner too late or too heavy)

3. The Algorithm “Black Box” Problem

Neither Garmin nor Wahoo fully discloses its algorithm details. This means:

• You can’t verify whether the calculations are correct
• Values from different brands can’t be directly compared
• Algorithm updates may suddenly change your scores

Recommended Usage Strategies

Best Practices

1. Look at trends rather than single-day values: Three consecutive days of Training Readiness below 40 is more concerning than an occasional low score

2. Combine with subjective feelings: Rate your fatigue, mood, and sleep quality on a 1-10 scale and cross-reference with device data

3. Establish a personal baseline: Use 2-3 months to establish your “normal range”—only adjust when you deviate from that baseline

4. Don’t be held hostage by the data: If Training Readiness shows 40 but you feel great, try training and see how you respond in the first 10 minutes

5. Pre-race strategy: Starting 3 days before an important race, focus on Training Readiness and HRV trends to ensure you reach a Peaking state

Taiwan-Specific Considerations

Taiwan’s high temperature and high humidity environment affects HRV and recovery metrics. When training in summer:

• Training Readiness will generally drop by 5-15 points
• This doesn’t necessarily mean you haven’t recovered—your body is dealing with heat stress
• Give yourself a 7-14 day heat adaptation period, and the numbers will gradually recover
• Early morning training (5:00-7:00 AM) can reduce heat stress interference with your data

Tech metrics are supporting tools, not the master. Learn to read their language, but always keep your own judgment.

Related Reading

• A Complete Guide to Garmin Connect Training Data: A Practical Guide to Body Battery and Training Status Metrics
• Running Data Analysis: Interpreting Training Load Metrics on Garmin / COROS
• The Complete Guide to Interpreting Garmin Connect Data: Beyond Mileage Tracking
• Training Load Too High Warning: How to Use Data to Prevent Overtraining