Glycogen Calculator: Post-Workout Carb Intake Planner

Plan post-exercise carbs: total grams, the first 30-minute dose and hourly amounts until your next session, from weight, duration and intensity.

1-Click Athletic Training Profiles:

Session Duration & Recovery Window

Total Carbs Needed
126.0Grams

Total carbohydrate budget to restore liver & muscle glycogen.

Immediate 30-Min Bolus
37.8Grams

Rapid-phase intake to maximize insulin-independent GLUT-4 transport.

Hourly Feeding Rate
16.0g / hour

Steady hourly intake sustained until your next training session.

Carbohydrate Dosing Schedule (Grams per Feeding)

Visual distribution of immediate rapid bolus followed by sustained hourly replenishment feedings.

Detailed Feeding Schedule Table

Feeding StageTarget Carbohydrates (g)Example Food Options
First 30m37.8 g1-2 ripe bananas, 500ml sports drink, or energy gel
Hour 116 g1 cup rice, oatmeal, sweet potato, or bagel
Hour 216 g1 cup rice, oatmeal, sweet potato, or bagel
Hour 316 g1 cup rice, oatmeal, sweet potato, or bagel
Hour 416 g1 cup rice, oatmeal, sweet potato, or bagel
Hour 516 g1 cup rice, oatmeal, sweet potato, or bagel
Hour 68 g1 cup rice, oatmeal, sweet potato, or bagel

Muscle & Liver Glycogen Replenishment Physiology

Glycogen represents the primary stored form of glucose in the human body, sequestered predominantly within skeletal muscle tissue (~400 to 500 grams in trained adults) and the liver (~80 to 100 grams). During prolonged aerobic exertion and high-intensity glycolytic training, intramuscular glycogen stores become substantially depleted, resulting in peripheral fatigue, reduced power output, and impaired muscle contraction velocity ('hitting the wall').

Rapid glycogen resynthesis is especially critical when athletes perform two sessions within the same day or have less than 8 hours of inter-bout recovery. Immediately post-exercise, muscle cell membranes exhibit heightened insulin-independent GLUT-4 glucose transporter translocation, enabling rapid cellular glucose uptake at rates up to 5% to 7% per hour when carbohydrates are ingested promptly.

The Two-Phase Post-Workout Carb Timing Protocol

  • **Phase 1: Immediate 30-Minute Window (Rapid Phase)**: Consume 30% of total carbohydrate needs (up to 50 grams) within 30 minutes post-cessation. High-glycemic, low-fiber sources (glucose, maltodextrin, ripe fruit, sports beverages) capitalize on elevated glycogen synthase enzyme activity.
  • **Phase 2: Sustained Hourly Refueling (Slow Phase)**: Distribute the remaining carbohydrate quota across equal hourly feedings until the subsequent training bout. Co-ingesting 20–25g of protein enhances insulin secretion and stimulates muscle protein synthesis.

Hand-Verified Carbohydrate Replenishment Case Studies

**Case 1: Moderate Endurance Session (70 kg, 90 minutes, Moderate Intensity (1.2g/kg/hr), 6 hours until next workout)** • Exercise Duration: 90 / 60 = 1.5 hours • Total Carbohydrate Need: 70 × 1.2 × 1.5 = 126.0 grams • Phase 1 (Immediate 30-min Dose): min(126.0 × 0.30, 50 g) = min(37.8, 50) = 37.8 grams • Remaining Carbohydrate Pool: 126.0 - 37.8 = 88.2 grams • Effective Hourly Window: 6.0 - 0.5 = 5.5 hours • Hourly Feeding Rate: 88.2 / 5.5 = 16.04 grams per hour (five 16.0g feedings followed by one 8.0g final dose)

**Case 2: High-Intensity Two-a-Day Bout (80 kg, 60 minutes, High Intensity (1.5g/kg/hr), 4 hours until next session)** • Exercise Duration: 60 / 60 = 1.0 hour • Total Carbohydrate Need: 80 × 1.5 × 1.0 = 120.0 grams • Phase 1 (Immediate 30-min Dose): min(120.0 × 0.30, 50 g) = min(36.0, 50) = 36.0 grams • Remaining Carbohydrate Pool: 120.0 - 36.0 = 84.0 grams • Effective Hourly Window: 4.0 - 0.5 = 3.5 hours • Hourly Feeding Rate: 84.0 / 3.5 = 24.0 grams per hour

Practical Post-Workout Food Equivalents

  • **~25 Grams Carbohydrates**: 1 large ripe banana | 1 packet standard energy gel | 350ml sports drink | 1 slice white toast with 1 tbsp honey.
  • **~50 Grams Carbohydrates**: 1 cup cooked jasmine/white rice | 500ml low-fat chocolate milk | 2 large bananas | 1 large plain bagel.

Formulas Used

Total Carbohydrate Burden

TotalCarbs_g = BodyWeight_kg × IntensityFactor × (Duration_min / 60)

Estimates post-exercise glucose replenishment demands based on body mass and duration, weighted by session intensity (Low: 1.0, Moderate: 1.2, High: 1.5 g/kg/hr).

Immediate Post-Exercise Bolus

ImmediateCarbs = min(TotalCarbs × 0.30, 50)

Caps immediate rapid-phase carbohydrate intake at 50 grams within 30 minutes to optimize glycogen synthase without causing gastrointestinal osmotic distress.

Hourly Sustained Rate

HourlyCarbs = (TotalCarbs - ImmediateCarbs) / max(0.5, HoursUntilNext - 0.5)

Distributes remaining carbohydrate needs into steady hourly feedings across the remainder of the inter-session recovery interval.

Variables Explained

Body Weight

Duration

Intensity Level

Time Until Next Session

Important Notes

•

This calculator provides general sports nutrition estimation models for endurance and multi-session athletes.

•

Individuals with diabetes, insulin resistance, or metabolic conditions should consult a registered sports dietitian or endocrinologist before following high-glycemic carbohydrate protocols.

Frequently Asked Questions

International Society of Sports Nutrition (ISSN) guidelines recommend 1.0 to 1.2 grams of carbohydrate per kg of bodyweight per hour during the first 4 hours of recovery after exhaustive exercise, or approximately 30–50g immediately post-session followed by regular meals.
Under optimal nutritional conditions with sufficient carbohydrate intake, complete skeletal muscle glycogen resynthesis requires 20 to 24 hours. For athletes training twice per day, rapid post-exercise carb refueling is essential.
Glycogen is the body's primary stored form of carbohydrate. Muscle glycogen fuels high-intensity anaerobic and aerobic glycolysis, while liver glycogen maintains normal blood glucose concentrations and fuels central nervous system cognition during exercise.
Yes, particularly if you are training again within 8 hours. Glycogen synthase activity and non-insulin-mediated glucose uptake (via GLUT-4) peak during the first 30–45 minutes post-exercise, leading to significantly faster storage rates than delayed feedings.
Yes. Co-ingesting 0.2–0.4 grams of protein per kg of bodyweight alongside carbohydrates stimulates greater insulin secretion from pancreatic beta cells, which accelerates glucose uptake into muscle tissue and enhances simultaneously elevated protein synthesis.
Depleting muscle glycogen causes extreme physical and mental fatigue, commonly called 'hitting the wall' or 'bonking.' The body must rely primarily on beta-oxidation of fatty acids, which cannot sustain high-intensity mechanical power output.
For immediate recovery (first 1–2 hours), high-glycemic simple carbohydrates (white rice, potatoes, bananas, dextrose, sports drinks) are superior because they rapidly elevate blood glucose and insulin. Later in the day, complex fibrous carbs are ideal.
No. If your session was low intensity (e.g., light walking or easy recovery yoga) or if your next workout is 24+ hours away, normal balanced meals with adequate daily carbohydrates will naturally restore glycogen without specialized dosing schedules.

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Quick Tips

  • 1Track progress consistently
  • 2Consider rest and recovery
  • 3Set realistic fitness goals
  • 4Consult trainers for guidance