Sport és vércukor: CGM-alapú edzés-optimalizálás

Sport and Blood Sugar: CGM-based Exercise Optimization

May 13, 2026 Allulose Store

What does CGM show during exercise?

Continuous Glucose Monitoring (¹CGM) has revolutionized real-time blood sugar tracking, especially during sports, where dynamic changes in glucose levels are crucial for performance and safe exercise.

In this article, we'll review how the body reacts to exercise, what ¹CGM measures, and how the data obtained can be applied in practice.

CGM Basics for Athletes

CGM sensors measure glucose concentration in the interstitial fluid under the skin, with a delay of approximately 1-3 minutes compared to actual blood glucose levels, thus drawing a detailed curve during exercise.

The normal range is between 70-140 mg/dL (3.9-7.8 mmol/L), but fluctuations are common depending on intensity – for example, below 70 mg/dL during hypoglycemia, and above 180 mg/dL during hyperglycemia.

CGM apps offer trend lines, arrows, and alarms, aiding in prevention.

Effect of Exercise Types on Blood Sugar

Low-to-moderate intensity aerobic exercise (²LISS: walking, running, cycling for 30+ minutes) typically lowers blood sugar because muscles utilize glucose, even without insulin.

High-intensity intervals (³HIIT: sprints, weightlifting), however, raise it due to stress hormones (adrenaline, cortisol) which release glucose from the liver.

Long workouts (e.g., hiking) can predict hypoglycemia 15-30 minutes in advance with a declining trend, allowing for timely intervention.

Exercise Type	Blood Sugar Change	CGM Pattern	Example
Aerobic (moderate)	Decrease	Downward arrow, below 85 mg/dL	Cycling 1 hour
Anaerobic (high)	Increase	Upward arrow, 140+ mg/dL	Sprinting, ³HIIT
Long endurance	Late decrease	Slow drop, risk of hypoglycemia	Hiking 2+ hours

Practical Tips with CGM Data

Before exercise, start above 85 mg/dL with slow-digesting carbohydrates (e.g., oats) to avoid reactive hypoglycemia 15-75 minutes later.

During exercise, if the trend is dropping below 85 mg/dL, drink a sports drink or eat a banana – wait 5-10 minutes for the effect while moderating intensity.

Afterwards, re-measure and correct with a protein-carbohydrate combo to prevent rebound; avoid dehydration with continuous water intake.

Advantages and Limitations

CGM optimizes performance with fuel management, reduces hypoglycemia risk (symptoms: dizziness, weakness below 70 mg/dL), and provides personalized protocols.

Limitation: Sensor accuracy during intense movement may deviate by ±10-20% from fingerstick measurements, plus individual factors (hunger, infection) can influence it.

Regular self-monitoring (pre-/during-/post-exercise measurements) can stabilize blood sugar, making sports not only safe but also health-optimizing.

How to Interpret the CGM Curve After Exercise

The CGM curve after exercise is crucial for observing glucose level recovery, as the body replenishes glycogen stores and adapts to the exertion at this time.

This helps identify the risk of hypoglycemia or excessive rebound, providing a personalized nutrition and rest strategy.

Normal Reactions After Exercise

After exercise, a glucose decrease lasting typically 30-120 minutes is observed with aerobic loads, because muscles continue to take up glucose independently of insulin.

This gradually normalizes within the 70-140 mg/dL (3.9-7.8 mmol/L) range.

With anaerobic exercise (e.g., weightlifting), a brief rise (due to stress hormones) is followed by stabilization.

If the curve does not return after 90 minutes, dehydration or insufficient carbohydrate intake might be the underlying cause.

Warning Patterns

Downward-sloping curve

A drop below 70 mg/dL 1-2 hours later indicates hypoglycemia.

Fast-acting carbohydrates (e.g., 15g glucose) are needed, followed by a 15-minute wait and recheck.

Upward-sloping curve

180+ mg/dL, 2 hours later, may indicate cortisol or adrenaline effects.

In this case, protein-rich food (e.g., cottage cheese + berries) helps stabilize.

Stagnant line

On an empty stomach, indicates lack of energy.

Curve Pattern	Time after exercise	Possible Cause	Action
Slow decrease	0-60 minutes	Normal glycogen uptake	Carbohydrate + protein (e.g., shake)
Sharp drop	30-90 minutes	Muscle glucose demand	Fast CH, rest
Rebound	60-120 minutes	Stress hormones	Protein, low ⁸GI food
Stagnation	90+ minutes	Dehydration	Water, electrolytes

Interpretation Tips

Look at trend arrows and ⁴AUC (area under the curve) in a 2-4 hour window.

For a decreasing trend, consume 0.5g/kg body weight of ⁵CH per hour.

For an increasing trend, avoid high ⁸GI foods.

Compare with pre-exercise values to fine-tune the protocol (e.g., more fat beforehand if prone to drops).

Apps (e.g., Supersapiens) should provide nocturnal alerts for delayed effects.

Long-term, log patterns with meals to optimize performance.

How to Monitor Recovery Until Sleep

Using CGM to monitor recovery from exercise until sleep (typically a 2-6 hour window) is crucial for assessing glycogen replenishment, changes in insulin sensitivity, and the risk of hypoglycemia.

During this time, stabilization of the curve indicates optimal recovery, while fluctuations require fine-tuning in nutrition or rest.

Normal Recovery Curve

In the 1-2 hours post-exercise, a slight glucose decrease is expected: 70-100 mg/dL, 3.9-5.6 mmol/L, followed by a gradual rise and stabilization: 90-140 mg/dL, 5-7.8 mmol/L before sleep, as muscles take up glucose.

Downward-pointing arrow (low trend)

Acceptable for up to 3 hours if it doesn't drop below 70 mg/dL.

Upward-sloping (high trend)

May indicate residual cortisol, alongside normal glycogen synthesis.

Problematic Patterns and Causes

If there's a sharp drop 2+ hours after exercise (e.g., below 60 mg/dL, 3.3 mmol/L), muscle glucose demand or insufficient post-exercise carbohydrate intake might be the cause – rapid ⁵CH intake (15-30g) is recommended.

Stagnant or fluctuating curve (narrow band, 80-110 mg/dL, 4.4-6.1 mmol/L)

Indicates dehydration or low caloric intake.

Rise to 160+ mg/dL, 8.9+ mmol/L

Rebound due to too many fast ⁵CH.

Curve Pattern	Time from Exercise	Meaning	Correction
Slight decrease then stable	0-4 hours	Good glycogen uptake	Protein+CH (e.g., yogurt+fruit)
Sharp drop	1-3 hours	Hypoglycemia risk	Fast glucose, salted water
Over-elevation	2-5 hours	Stress/CH-excess	Low GI food, rest
Fluctuation	Entire window	Imbalance	Electrolytes, smaller portions

Practical Observation Until Sleep

Check trend arrows and timed values every 30 minutes (e.g., exercise +1h, +3h, before bedtime).

Aim for 100-120 mg/dL, 5.6-6.7 mmol/L at the start of sleep to prevent nocturnal drops.

Log with meals (e.g., 0.8g CH/kg within 2 hours) and Time in Range (⁶TIR >70% in 70-140 mg/dL, 3.9-7.8 mmol/L).

If patterns repeat, increase pre-exercise fats or set alarms for 70/180 mg/dL, 3.9-10 mmol/L.

Long-term, this maximizes recovery and performance.

What CGM Indicators Show Better Exercise Adaptation?

Analysis of CGM indicators suggests exercise adaptation if they show more stable glucose levels, improved insulin sensitivity, and fewer fluctuations over time, reflecting the body's adjustment to stress.

These metrics are derived from long-term trends (2-4 weeks), not from a single workout.

Key Indicators for Better Adaptation

High Time In Range (⁶TIR >85%: between 70-140 mg/dL, 3.9-7.8 mmol/L, over 24 hours) indicates that the body manages glucose more efficiently around exercise, with fewer hypoglycemic or hyperglycemic events.

Lower glucose variability (⁷CV <25%, decreasing standard deviation) means more stable curves in post-exercise recovery, suggesting better mitochondrial adaptation.

Exercise-Specific Signs

Smaller peaks during exercise (e.g., <160 mg/dL, <8.9 mmol/L for anaerobic loads) and faster return to normal range (within 1-2 hours) indicate better glycogen utilization, while stable 90-120 mg/dL, 5-6.7 mmol/L before sleep points to optimal hormonal balance.

Decreasing ⁴AUC (area under the curve in the exercise+4h window) signals less stress hormone response, confirming adaptation.

Indicator	Sign of good adaptation	Poor adaptation	Example
⁶TIR	>85% 24h	<70%	Stabilizes over weeks
⁷CV	<25%	>36%	Less fluctuation after exercise
Post-exercise ⁴AUC	Decreasing trend	High/increasing	Faster glycogen replenishment
Nocturnal minimum	>80 mg/dL	<70 mg/dL	Better recovery until sleep

How to Track

Monitor changes in ⁶TIR/⁷CV in weekly reports before/after exercise series.

If it improves, increase load; if it worsens, rest or fine-tune nutrients (e.g., more protein).

Individual logging with diet and sleep quality clarifies whether adaptation is genuine.

What CGM Pattern after Exercise is Considered Ideal?

The ideal post-exercise CGM pattern is a stable, slightly decreasing then leveling-off curve, indicating efficient glycogen replenishment and good insulin sensitivity with minimal fluctuations.

This typically remains within the 70-140 mg/dL (3.9-7.8 mmol/L) band, with low variability (⁷CV <25%).

Characteristics of the Ideal Curve

An initial slight decrease (e.g., 10-20 mg/dL, 0.5-1 mmol/L drop) in the 0-60 minutes after exercise is normal due to muscle glucose uptake, followed by stabilization within 1-3 hours around 90-120 mg/dL, 5-6.7 mmol/L, with a flat line before bedtime.

No sharp drop below 70 mg/dL, 3.9 mmol/L, nor rebound above 160 mg/dL, 8.9.

The trend arrow points at most slightly down or up, then becomes horizontal.

Why is this Ideal?

This pattern indicates high ⁶TIR (>90% in the 4-hour window) and low ⁷AUC, reflecting rapid recovery, less stress hormone response, and better adaptation – ideal for performance optimization.

For example, faster stabilization after aerobic exercise (running) shows better mitochondrial capacity.

Time Point	Ideal Value	Trend	Note
+0-30 min	85-110 mg/dL	Slight ↓	Glycogen uptake
+1 hour	90-120 mg/dL	Stabilizes	CH+protein effect
+2-4 hours	95-125 mg/dL	→ horizontal	Ready for sleep
Entire window	⁶TIR >90%	⁷CV <20%	Optimal recovery

How to Achieve This

After exercise, consume 0.5-0.8 g/kg slow ⁵CH + 20-30g protein (e.g., quinoa+yogurt) within 30 minutes, with hydration.

Avoid high glycemic index (⁸GI) foods/drinks to prevent rebound.

If there's a deviation, fine-tune (e.g., more fat beforehand), and follow the trend in the app for 1-2 weeks.

This graph illustrates the relationship between blood glucose levels and physical/mental performance.

Adaptation

The body's adaptation to exercise, where it becomes stronger, more enduring, and more efficient due to stress – this is the goal of sports.

What does adaptation look like on CGM?

1st → 3rd week: Improving patterns,

⁶TIR: 75% → 88% (more time in 3.9-7.8 mmol/L)

⁷CV: 35% → 22% (less fluctuation)

Post-exercise ⁴AUC: Large → Small (faster stabilization)

Example: After a run, it initially returns to 5.6 mmol/L in 2 hours, but after 3 weeks, it does so in 30 minutes.

3 Phases of Adaptation

1. Damage (during exercise): ↑ ⁷CV, ↓ ⁶TIR

2. Recovery (0-48 hours): CGM stabilizes

3. Supercompensation (48-96 hours): New, higher level

¹⁰HRV improves
CGM more stable
Performance increases

CGM Signs: When are you adapting?

Good adaptation	Stalled adaptation	Overtraining
TIR ↑ (>85%)	TIR stagnant	TIR ↓ (<70%)
CV ↓ (<25%)	CV slight ↑	CV ↑ (>36%)
Faster recovery	Slower stabilization	Night peaks
HRV improves	HRV stagnant	HRV ↓

Practical rule: When to increase the load?

⁶TIR >85% AND ⁷CV <25% for 2 weeks → +10% load
Stable post-workout curve (5-6.7 mmol/L in 2 hours)
¹⁰HRV above baseline, or stable

Example workout log:

Week 1: ³HIIT, ⁶TIR 78%, ⁷CV 32% → Recovery
Week 2: HIIT, TIR 84%, CV 26% → Wait!
Week 3: HIIT, TIR 89%, CV 21% → You can increase the intensity!

What happens if you increase too soon?

⁶TIR drops → ⁷CV increases → ¹⁰HRV decreases
→ Overtraining spiral: injury, loss of motivation

Golden rule: "If your CGM and ¹⁰HRV say you're ready, increase. If not, rest more."

If adaptation is not linear: 3 steps forward, 1 back!

CGM helps you notice in time whether supercompensation or overload has occurred!

What CGM deviation indicates overtraining or insufficient recovery?

CGM deviations indicate overtraining or insufficient recovery if they show higher glucose variability (⁷CV >36%), persistently higher average values, or prolonged post-exercise excursions, which suggest chronic stress and weaker insulin sensitivity.

These patterns, repeating every 3-7 days, indicate the need for rest.

Signs of overtraining on CGM

A higher baseline (average >140 mg/dL, 7.8 mmol/L in 24 hours) and frequent hyperglycemic peaks (>180 mg/dL, >10 mmol/L without exercise) indicate cortisol dominance, while nocturnal rises (e.g., after 2-4 hours of sleep) signal impaired recovery.

Decreasing ⁶TIR (<70% in 70-140 mg/dL, 3-7.8 mmol/L) and a larger ⁴AUC in the 4 hours post-exercise (slow stabilization) are observed with fatigue.

Patterns of insufficient recovery

Sharp or prolonged hypoglycemic episodes (>20% time below 70 mg/dL, 3.9 mmol/L at night), a fluctuating curve (rapid up-down arrows), or stagnation around 80-110 mg/dL approaching sleep indicate glycogen depletion, often with subtle symptoms like fatigue or loss of motivation.

Worsening trends after weekend workouts (e.g., high ⁷CV on Sunday) warn of overload.

Deviation	Duration	Cause	Action
Persistent elevation	24h average >140 mg/dL	Overtraining, cortisol	2-3 days of reloading, sleep
Frequent hypoglycemia at night/	Night/ after +4h	Glycogen depleted	Rest, excess carbs
High ⁷CV (>36%)	Post-workout window	Stress/imbalance	No exercise, blood test
Low ⁶TIR	Weekly trend	Average lack of recovery	Nutrition, ¹⁰HRV check

How to act

If ⁷CV increases or ⁶TIR drops by 10%+ within 1 week, take 48 hours of passive rest, check iron/ferritin with lab tests, and fine-tune (more sleep, low intensity).

In the long term, incorporate 1-2 reload days per week for sustainable adaptation.

CGM rules for fat burning

During fat burning, CGM rules focus on low, stable glucose levels, which promotes fatty acid mobilization and minimal insulin response, thus maximizing lipolysis during exercise and rest.

Goal: daily average 80-110 mg/dL (4.4-6.1 mmol/L), high ⁶TIR (>85% in 70-120 mg/dL, 3.9-6.7 mmol/L range), low ⁷CV (<20%) to maintain a fat-burning metabolic state.

Basic CGM rules for fat burning

Before exercise, maintain 85-100 mg/dL, 4.7-5.6 mmol/L (avoid ⁵CH, use fats/protein)
During exercise, allow it to drop to 70-95 mg/dL, 3.9-5.3 mmol/L in the fat-burning zone (60-70% max heart rate), which indicates glucose sparing and fat utilization.
Afterward, stabilize around 80-105 mg/dL within 1-4 hours with low ⁸GI food (e.g., salad + chicken), avoiding rebound; nocturnal minimum >75 mg/dL, >4.2 mmol/L.

Optimal fat-burning patterns

Good sign: even ↓ trend during exercise (no peaks), post-exercise flat line in a low range (⁶TIR >90% in a 4h window), stable 85-100 mg/dL, 4.7-5.6 mmol/L at night – this indicates higher fat burning with better insulin sensitivity.

Weekly trend: decreasing average glucose and ⁷CV show fat adaptation; if it rises, reduce calories or increase aerobic load.

Period	Target value	Rule	Tip
Before exercise	85-100 mg/dL	Stable →	Black coffee, BCAA
During exercise	70-95 mg/dL	Slow ↓	Fat-burning zone, water
After +0-2h	75-100 mg/dL	Stabilize	Fat/protein (avocado + egg)
+2-6h / until sleep	80-105 mg/dL	Flat →	Vegetables + fish, ⁶TIR>85%
Daily average	85-105 mg/dL	⁷CV<20%	Calorie deficit, fasting

Practical application

Log: if ⁶TIR improves and the average drops, maintain the deficit (500 kcal)

For hypoglycemia, add electrolytes; for hyperglycemia, fewer ⁵CH.

Combine with ²LISS (low-intensity steady state) workouts in the fat-burning zone, with app alerts for 70/120 mg/dL, 3.9-6.7 mmol/L – this aims for sustainable 0.5-1 kg/month fat reduction without muscle loss.

Which types of exercise best support fat metabolism?

The exercise types that best support fat metabolism are those that are sustained low-intensity, long-duration (fat-burning zone: 60-70% max heart rate), or combine high-intensity intervals, thereby maximizing lipolysis and post-exercise afterburn (¹²EPOC).

These enhance insulin sensitivity and promote fatty acid oxidation while preserving muscles.

Top exercise types for fat metabolism

Brisk walking/fast walking: 45-90 minutes, in the fat-burning zone – up to 60-80% of energy comes from fat, minimal muscle fatigue.

Cycling (moderate pace): 60+ minutes, steady – excellent endurance fat burner, low impact.

³HIIT (high-intensity interval training): 20-30 minutes (e.g., sprint/quarter minute rest) – short, but due to high ¹²EPOC, it boosts fat burning for 24-48 hours.

Combined strength + aerobic: 2-3x per week strength training (muscle building, conditioning) + 3x ²LISS (low-intensity steady state exercise, e.g., rowing).

Why are these effective?

Aerobic/²LISS exercises directly target fat burning (mobilization of fatty acids at low glucose levels), while ³HIIT/strength training increases basal metabolism in the long term (muscle mass increase + mitochondrial adaptation).

Exercise Type	Type of Fat Burning	Recommended Time/Week	Calorie Burn Example (60kg)
Brisk walking	Direct fat	150-300 minutes	250-400 kcal/hour
Cycling	Direct + ¹²EPOC	120-240 minutes	400-600 kcal/hour
³HIIT	Afterburn	60-90 minutes	500+ kcal + 15% extra 24h
Strength + aerobic	Long-term metabolism	3-5x 45 minutes	300 kcal + muscle growth

CGM connection for fat burning

In this zone, CGM shows a slow ↓ trend stabilized between 70-100 mg/dL, 3.9-5.6 mmol/L – indicating fatty acid mobilization with minimal insulin.

If it rises to 120+ mg/dL, 6.7 mmol/L, the intensity is too high (glucose dominates).

Practice: Brisk walk/cycle for 45-90 minutes at this heart rate = optimal fat burning (250-500 kcal/h, 60%+ from fat) combined with a calorie deficit.

Practical tips

Start with 150 minutes of ²LISS per week, incorporate 1-2 ³HIIT sessions.
Measure heart rate (max x 0.6-0.7) for the fat-burning zone.
Combine with a calorie deficit (500 kcal) for 0.5-1 kg/month fat loss without losing muscle.

Gradually increase volume in the long term for sustainability.

Timing of protein intake

The timing of protein intake is crucial for fat burning and muscle mass retention, as its even distribution maximizes protein synthesis, supports insulin sensitivity, and reduces hunger during a calorie deficit.

Goal: 1.6-2.2 g/kg body weight protein daily, divided into 4-5 meals (20-40 g/serving) to stabilize the CGM curve (⁶TIR >85% in 80-120 mg/dL, 4.4-6.7 mmol/L).

Optimal timing rules for fat burning

Morning/after waking: 25-30 g (e.g., eggs + smoothie) – prevents muscle breakdown after overnight fasting, stable start for CGM (starting value 90-110 mg/dL, 5-6.1 mmol/L).

Before workout (1-2 hours): 20-30 g slow-digesting protein (casein/cottage cheese) – nutrient for glycogen sparing, without a sharp rise.

After workout (within 0-30 minutes): 30-40 g fast-digesting protein (whey) + minimal CH – anabolic window, rapid stabilization to 80-100 mg/dL on CGM.

Before bed (1-2 hours): 30-40 g slow-digesting protein (casein/cottage cheese) – nocturnal regeneration, prevents hypoglycemia during sleep (>80 mg/dL, >4.4 mmol/L minimum).

Why is timing critical?

Uneven intake (e.g., only lunch/dinner) reduces muscle strength and increases ⁷CV on CGM.

Balanced distribution improves fat burning by 15-20% through ¹²EPOC, while preserving muscles in a deficit.

Time	Protein/serving	CGM target	Example
Morning	25-30 g	90-110 mg/dL stable	Egg whites + spinach
Before workout	20-30 g	Slight ↑	Cottage cheese + nuts
After workout	30-40 g	Rapid ↓→stable	Whey shake + berries
Before bed	30-40 g	90-110 mg/dL flat	Casein + peanut butter

Practical tip with CGM

If the post-workout curve spikes to >130 mg/dL, >7.2 mmol/L, reduce ⁵CH with protein.

If it drops to <70 mg/dL, 3.9 mmol/L at night, increase the evening dose.

Fine-tune based on weekly reports – this ensures sustainable fat reduction (0.5-1 kg/month) without muscle loss.

The infographic shows what happens in the body if we consume a significant amount of carbohydrates 45 minutes before starting exercise.

There is an unfavorable 30-90 minute window for pre-exercise meal timing that significantly affects the risk of reactive hypoglycemia: Study

Glycogen sparing

The body's strategy to burn fat instead of glycogen (carbohydrate stores in muscles/liver) during low-to-moderate intensity exercise, thus preserving reserves for longer durations or subsequent workouts.

When does it happen on CGM?

Fat-burning zone (60-70% HRmax): 3.9-5.6 mmol/L slow ↓ trend

→ Glycogen "sparing" = fatty acid mobilization

→ After 45+ minutes, 60-80% of energy comes FROM FAT

Example: Brisk walk 90 minutes – glycogen remains almost unchanged, fat is burned.

How do you support it with CGM?

Why is it important for athletes?

Long-duration workouts: Glycogen remains for the endgame
2 workouts daily: After morning ²LISS, afternoon ³HIIT has fuel
Fat burning: Low glucose = high lipolysis

Practical protocol

Before workout: Black coffee + BCAA (4.7-5.6 mmol/L)
During workout: Water + electrolytes (maintain 3.9-5.3 mmol/L)
60+ minutes ²LISS: Fat-burning zone (60-70% HRmax)
CGM check: If <3.9 mmol/L → 10g CH, if >6.7 → slow down!

Golden rule: "Low glucose + low heart rate = maximum glycogen sparing"

Example daily routine:

7:00 Morning ¹⁰HRV: 75ms
8:00 CGM: 5.0 mmol/L → 90min brisk walk (¹¹HR 125 bpm)

9:45 CGM: 4.2 mmol/L → Glycogen sparing successful!

11:00 Recovery: ¹³Whey + oats → stabilization at 5.6 mmol/L

This is the basis of fat adaptation – over time, you use less glycogen and more fat at the same intensity!

Summary

Continuous Glucose Monitoring (CGM) revolutionizes athletic performance and recovery with real-time blood glucose data (measured in mmol/L), assisting in glycogen management, hypoglycemia avoidance, and targeted metabolic adaptation.

This summary organizes CGM patterns around workouts, target efforts, recovery, and targeted strategies for muscle gain/fat loss.

CGM basics during exercise

Normal range: 3.9-7.8 mmol/L. Hypoglycemia <3.9 mmol/L, hyperglycemia >10 mmol/L.

Aerobic exercise (running, cycling): Decrease (↓ arrow), muscle glucose uptake.

Anaerobic/³HIIT: Increase (↑ arrow, due to adrenaline), then decrease.

Ideal: Stable 4.4-7.2 mmol/L during exercise, rapid drop within 1 hour.

Workout Type	Blood Glucose Change	CGM Pattern	Example
Aerobic	Decrease	↓ below 4.7 mmol/L	1 hour Cycling
³HIIT	Increase	↑ 7.8+ mmol/L	Sprint

Post-workout Recovery (0-6 hours)

Ideal Curve: Slight ↓ (3.9-6.1 mmol/L 0-60 min), stabilization at 5-6.7 mmol/L for 1-4 hours, flat line before sleep.

Warning: Sharp ↓ <3.9 mmol/L (15-30g fast CH), rebound >10 mmol/L (protein+low ⁸GI).

Pre-sleep Target: 5.6-6.7 mmol/L, ⁶TIR >90% in a 4-hour window.

Time	Ideal	Problem	Action
+0-30m	4.7-6.1 mmol/L	<3.9 mmol/L	Fast CH (banana)
+1-2h	5-6.7 mmol/L	>8.9 mmol/L	Protein+CH shake
+4h	5.3-7 mmol/L	Fluctuating	Electrolytes

Signs of Adaptation and Overtraining

Better Adaptation: ⁶TIR >85% (3.9-7.8 mmol/L 24h), ⁷CV <25%, decreasing ⁴AUC post-workout.

Overtraining/Poor Recovery: Average >7.8 mmol/L, ⁷CV >36%, nocturnal peaks >8.9 mmol/L, frequent <3.9 mmol/L.

Indicator	Good Adaptation	Overtraining
⁶TIR 24h	>85%	<70%
⁷CV	<25%	>36%
Nightly min.	>4.4 mmol/L	<3.9 mmol/L

CGM Rules for Muscle Growth

Goal: Anabolic window, stable 5-7.2 mmol/L (⁶TIR >85%).

Before: 5.6-6.7 mmol/L (oats+whey).
After: 4.4-6.1 → stable 5.6-7.2 (0.8 g/kg CH + 30g protein).
Night: 5-6.7 mmol/L (casein).

Period	Target	Tip
Before workout	5.6-6.7 mmol/L	Slow CH+protein
+0-2h	4.4-6.1 mmol/L	Shake (rice+chicken)
Until sleep	5.6-7.2 mmol/L	Casein+curd cheese

CGM Rule for Fat Burning

Goal: Fatty acid mobilization, low stable 4.4-6.1 mmol/L (⁷CV <20%).

Before: 4.7-5.6 mmol/L (fat/protein).

60-70% HRmax zone: 3.9-5.3 mmol/L slow ↓ (²LISS).

After: Stable 4.4-5.8 mmol/L (avocado+egg).

Period	Target	Tip
During workout	3.9-5.3 mmol/L	Fat burning zone
+2-6h	4.4-5.8 mmol/L	Vegetables+fish
Daily average	4.7-5.8 mmol/L	Calorie deficit

Best Workout Forms for Fat Metabolism

Fat Burning Zone (60-70% ¹¹HRmax): Brisk walking, cycling (150-300 minutes/week), ³HIIT (60 minutes/week for ¹²EPOC).

Workout	Fat Burning	Time/week
Walking	60-80% fat	150-300 minutes
Cycling	Direct+¹²EPOC	120-240 minutes
³HIIT	Afterburn	60-90 minutes

Protein Timing for Fat Loss (1.6-2.2 g/kg body weight)

Distributed over 4-5 meals (20-40 g/serving) for a stable CGM curve:

Morning: 25-30 g (eggs) – 5-6.1 mmol/L start
Before workout: 20-30 g slow (curd cheese)
After: 30-40 g ¹³whey – fast stabilization
Night: 30-40 g casein – >4.4 mmol/L minimum

Summary Protocol

Before workout: 5-6.7 mmol/L, protein+slow ⁵CH.
Workout: Fat burning: 3.9-5.3 mmol/L (60-70% ¹¹HRmax); muscle: 4.4-7.2 mmol/L.
After: 30-40 g protein + targeted ⁵CH, stabilization 4.4-6.7 mmol/L.

Weekly monitoring: ⁶TIR >85%, ⁷CV <25% – fine-tune with calories/training.

Overtraining: >7.8 mmol/L average or ⁷CV >36% = 48 hours rest.

Result: With targeted CGM guidance, 0.5-1 kg/month pure fat loss or muscle gain, with optimal recovery and performance.

English Abbreviations and Their Meanings

1) CGM

Continuous Glucose Monitoring — real-time tracking of tissue glucose

2) LISS

Low-Intensity Steady State — low-intensity, steady-pace exercise

3) HIIT

High-Intensity Interval Training

4) AUC

Area Under the Curve — usually indicates the total glucose load over time

5) CH

Carbohydrate(s)

6) TIR

Time in Range — the percentage of time blood glucose is within the target range (typically 3.9-10 mmol/L, for athletes often 3.9-7.8 mmol/L)

Target values in the context of our article:

Generally good: 70% (17 hours/day)
Optimal for athletes: 85% in 24 hours
Post-workout 4h window: 90%
Fat burning: 85% (3.9-6.7 mmol/L narrow band)

Example: If TIR is 92% on a training day, it indicates stable glycogen management and good adaptation.

7) CV

Coefficient of Variation

What does it measure? The degree of blood glucose fluctuation as a percentage (SD/mean × 100). The lower it is, the more stable the curve.

Target values

Example: CV 18% = flat, predictable curve; CV 42% = risk of frequent hypoglycemia/hyperglycemia.

How to use them together?

Good adaptation: TIR >85% and CV <25%
Overtraining: TIR <70% or CV >36%

Monitor in weekly reports: If ⁶TIR improves and CV decreases during the training series, the protocol is successful. If it worsens, rest or fine-tune (more sleep, less intensity).

These two numbers provide the CGM "traffic light":

green = optimal state,
yellow = fine-tuning needed,
red = rest/off-days.

8) GI

Glycemic Index — an indicator of the blood sugar-raising effect of foods

9) Post-workout

The phase after exercise when the body regenerates, replenishes glycogen stores, and repairs muscles – (0-4 hours).

What happens post-workout?

Physiology: Muscles continue to take up glucose (even without insulin), insulin sensitivity is maximal, an "anabolic window" opens for ~2 hours.

10) HRV

Heart Rate Variability

HRV measures the variations in time between heartbeats in milliseconds (R-R intervals) and indicates the balance of the autonomic nervous system – a perfect complement to CGM for recognizing recovery and overtraining.