Feeling energetic (vigor or vitality) is a positive feeling affecting the capacity to complete mental or physical activities.
Fatigue is a negative feeling resulting in reduced capacity to complete mental or physical activities.
Feelings of low energy and fatigue are quite common, affecting about one-fourth of the population.
In a review of this topic researchers looked at conditions that affected feelings of fatigue - obesity, smoking, heavy drinking, and presence of certain diseases such as arthritis, diabetes, high blood pressure, and depression. They also looked at the role of physical activity in promoting feelings of energy in 7 large population studies, and 15 experimental studies.
Each of these studies showed that the higher the level of physical activity, the more energy people had.
One large study in Australia included 39,532 women. Researchers calculated an activity score for each woman based on their reported exercise program. Possible scores ranged from 0 to 80 with 0 being the least active (no regular activity) and 80 the most active. The women also reported their feelings of energy or fatigue on an "energy-vitality scale." Sedentary women reported the most frequent feelings of low energy and fatigue. As women reported more weekly physical activity, they also reported more frequent feelings of high energy. The biggest improvement in feelings of energy came from those initially doing no exercise who started doing some regular exercise.
Another study included 1,758 people followed for 2 years. Their activity level and feelings of energy were evaluated twice during the 2 years. Researchers found that the total time spent exercising at the beginning of the study was a significant predictor of who would report feeling more energetic at the end of the 2-year study even after adjusting for potential confounders including age, BMI, education, gender, ethnicity, smoking, drinking, disease conditions, and poverty. Interestingly, exercise had the greatest benefit in increased energy for those who had health problems such as high blood pressure, diabetes, heart failure, and depression.
Exercise trial studies show similar increases in feelings of energy. One intervention study was made with depressed seniors. They exercised 45 minutes 3 times per week for 10 weeks. A control group didn't exercise but received health education on depression for an hour twice a week. After 10 weeks the exercise group showed a large increase in feelings of energy. The increase was 1.3 standard deviations, nearly a doubling of their reported energy levels. The control group, however, made no significant improvement in energy levels (see chart above).
In one study, heart failure patients who were sedentary started a 3-hour per week stepping exercise program. After 12 weeks the exercising heart patients showed a significant (1 standard deviation) improvement in energy levels.
All of the intervention trials showed uniformly positive improvements in energy even in those persons with health problems and chronic illness. The authors summarize their findings; "Sedentary people who feel fatigued are likely to experience a moderate to large increase in feelings of energy if they become regularly physically active."
So what kind of exercise is best for improving energy levels?
The study authors point out that for most people, and especially people who are older or have chronic health problems, moderate aerobic exercise (walking, stepping machine, stationary bicycling, etc.) is best, - 30 minutes 3-5 times weekly will show good results.
Also, choose exercises you enjoy (exercise to music, golf, active gardening, walking in the park, etc.).
Keep in mind that excessive exercise (too much too soon) may actually increase feelings of tiredness and fatigue, especially in persons not used to regular exercise.
The bottom line is clear: If you want to enjoy more energy in your life, regular, moderate physical activity is a key ingredient.
As always, if you have health problems, get your doctor's guidance as needed in developing a safe, effective activity program.