Why Do You Feel More Tired the More You Exercise?

When you first start hitting the gym, enthusiasm is high. But over time, many people find themselves feeling increasingly exhausted, sometimes even feeling completely drained. Today, let's explore why this happens and what you can do about it.

First, let's talk about a fascinating energy molecule called ATP (adenosine triphosphate). In our bodies, ATP acts like a small battery, providing energy for our muscles. During exercise, ATP breaks down into ADP (adenosine diphosphate) and energy. For ADP to convert back into ATP, it needs "fuel," primarily carbohydrates.

Here's the key point: if our bodies lack sufficient carbohydrates, the conversion rate of ADP to ATP decreases, making it difficult for muscles to sustain high-intensity exercise. Even worse, failed ADP conversion leads to its accumulation, increasing your fatigue.

Additionally, the central nervous system plays a significant role in our perception of fatigue. A neurotransmitter called serotonin (5-HT) can make us feel relaxed or even sleepy. Excessive exercise or poor nutrition increases the level of tryptophan crossing the blood-brain barrier, converting to more 5-HT, resulting in increased fatigue.

Factors Leading to Increased 5-HT:

1. Low Blood Sugar and Low Muscle Glycogen: When glycogen stores are low, the body breaks down muscle to create glucose, increasing the metabolism of branched-chain amino acids (BCAAs) and lowering their blood levels. This allows more tryptophan to cross the blood-brain barrier, promoting 5-HT production.

2. High-Tryptophan Foods: Foods rich in tryptophan, such as turkey (a Thanksgiving staple), can elevate tryptophan levels in the blood, leading to more 5-HT production and making you feel more fatigued during workouts.

3. High Fat Intake: Fats and tryptophan compete for the same protein carriers in the blood. High fat intake makes it easier for tryptophan to enter the brain, increasing 5-HT levels and causing you to tire more quickly.

Tips to Combat Exercise-Induced Fatigue:

1. Balanced Diet: Ensure adequate carbohydrate intake to fuel your muscles. Avoid excessive consumption of high-fat and high-tryptophan foods to prevent increased 5-HT production.

2. Supplement with BCAAs: BCAAs can compete with tryptophan to cross the blood-brain barrier, reducing 5-HT production. Consider supplementing with BCAAs before and after workouts to help delay fatigue.

3. Moderate Exercise: Over-exercising can lead to muscle fatigue and injury. Plan your workouts with appropriate intensity and volume to maintain long-term enthusiasm and prevent burnout.

4. Adequate Rest: Give your body enough time to recover. Avoid back-to-back high-intensity workouts that can lead to overtraining and excessive fatigue.

In summary, feeling more tired despite regular exercise is not without reason. There are complex biochemical mechanisms at play. By understanding these mechanisms, you can better adjust your diet and exercise habits, ensuring a more sustainable and effective fitness journey.