Combat fatigue with exercise

Did I hear you right? When I am tired and have no energy, I should exercise? That sounds rather counter intuitive to most people.

Researchers at University of Georgia studied the effect of chronic exercise training on sedentary young adults with a feeling of persistent fatigue (Psychother Psychosom 2008; 77: 167 – 1740). Thirty six healthy, young adults with persistent feelings of fatigue, were randomly assigned to low-intensity exercise (20 minutes of exercise on an exercise bike at a leisurely pace), moderate-intensity exercise (20 minutes of moderately intense exercise on an exercise bike) and no exercise control groups. Over a period of 6 weeks, participants visited the exercise laboratory 3 times per week. The vigour and fatigue mood state scores and aerobic fitness were measured before and after intervention. Those who were in the exercise groups felt up to 20% more energetic. Exercise also improved the fatigue symptoms but this was more obvious in the low-intensity exercise group. Interestingly, these improvements in feelings of energy and fatigue after exercise were not related to changes in their aerobic fitness.

In another study, researchers from Sacramento VA Medical Center examined the effect of a single session of exercise on the mood of regular exercisers and non-exercisers (Arch Phys Med Rehabil 2008; 89:358 – 363). Adult non-exercisers, moderate exercisers and ultra-marathon runners were instructed to exercise on a treadmill. All participants were asked to perform treadmill exercise at self-selected speeds to induce a rating of perceived exertion (RPE) of 13 (somewhat hard) for 20 minutes. This exercise period was preceded by 5 minutes at an RPE of 9 (very light) and ended with a 5 minute period of very light exercise. The study found that the acute exercise period increased vigor and reduced fatigue felt in the exercisers and ultra-marathon runners but had no effect on the non-exercisers. While the exercise did improve the mood in non-exercisers, this improvement was only half that seen in the regular exercisers.

When you are feeling a bit tired at the end of the day, the thought of skipping that usual exercise session is tempting. The excuse ‘I am too tired to exercise today’ may sound a bit hollow now. Even if you are tired, a period of less strenuous exercise may actually improve your mood and reduce that tired feeling. So, the next time you are feeling a bit tired, go for a walk or a swim. You might feel invigorated afterwards!