We think about maximising athletic performance in two categories: On-Hours and Off-Hours.
On-Hours = training or performance. Off-Hours = recovery and preparation.
In this article, we'll discuss:
- How does my body respond differently during On-Hours vs Off-Hours?
- How can I experiment to find what fuel sources work best for me?
How does my body respond differently during On-Hours vs Off-Hours?
Fueling is obviously key to optimal On-Hours Training. But fueling is also crucial to our Off-Hours recovery.
Here's the breakdown: Altering the availability of nutrients after exercise can impact the training response by modulating the exercise stimulus and/or the body’s ability to adapt to it.
On top of that, On-Hours and Off-Hours interact and influence each other. Therefore it’s important to consider the concept of nutrient timing across a continuum.
During moderate-to-high intensity exercise, blood glucose oxidation and muscle glycogen stores represent the most important fuel sources to sustain exercise.
In these training sessions, post-exercise nutrient timing should largely focus on the restoration of muscle glycogen to improve rates of recovery. The post-exercise time period was seen to represent an opportunity to enhance adaptation and recovery though nutrition due to the enhanced sensitivity of skeletal muscle to nutrient uptake and metabolism. This period lasts approximately 45-60 min while your muscles are more responsive to glucose uptake.
This phenomenon is known as ‘insulin-independent uptake’ which is, simply, a key window of opportunity to quickly recover your glycogen stores after exercise. It’s also a time frame where you can most influence your physical recovery and actually impact any upcoming output you have planned. In this period, an optimal restoration of muscle glycogen post-exercise can occur through carbohydrate intake of 1.0–1.5 g/kg/h. However, frequent carbohydrates feeding should continue for 4-to-6 hours after exercise. High glycemic index carbohydrates may be optimal for rapid muscle glycogen re-synthesis in this post-exercise time window.
So, yeah. It’s crucial. Rapidly and strategically intaking carbohydrates during this time period amplifies the body’s shift from a catabolic to a more anabolic state — ensuring adaptations and a quick recovery.
During Off-Hours, carbohydrates intake would help in better maintaining adequate glucose levels. Glucose level can then be used as a proxy to guide your post-exercise fueling approach. Many athletes maintain their glucose levels between 90-140 to ensure a proper glucose flux to their muscles. Dipping below 70 might actually impede your body’s ability to efficiently replenish glycogen stores.
And what does this mean for your recovery?
A lot. You can effectively promote recovery by adequately refueling right after you cool down, during this 45-60 minute glycogen replenishment window.
If you plan to make your refueling part of your post-workout routine, you’ll be better prepped for your next big output.
How can I experiment to find what fuel sources work best for me?
1. Perform a high-intensity exercise. Create an Exercise Event to track in your Supersapiens app.
2. Refuel within 60 minutes of completing your exercise. Pick an energy source that results in a moderately high glucose response, one that would typically spike you up to 130-140 mg/dL on a non-exercise day.
3. Create a Food Event. When setting the duration, start with when you first began your refueling and end two hours later, or as soon as your glucose levels return to your Target Average, whichever comes first. Tag the event with #recoverfaster.
4. Analyze your glucose response. Ask yourself: Was my glucose response less steep compared to the same Food Event on a non-training day?
Did this fuel source keep me above 70 mg/dL, while maintaining my glucose levels within 70-140 mg/dL over the following 4-5 hours?
5. Share your learnings. What fuel choice works for you? Connect, discuss, inspire and optimize in the Supersapiens Athletes Facebook group.
- Ivy JL, Kuo CH. Regulation of GLUT4 protein and glycogen synthase during muscle glycogen synthesis after exercise. Acta Physiol Scand. 1998 Mar;162(3):295-304. doi: 10.1046/j.1365-201X.1998.0302e.x. PMID: 9578375.