Athletes and Fatigue. Why am I so Tired?

“I feel tired a lot. What vitamins will give me more energy?”

“When I get home from work, I’m just too tired to cook dinner…”

“I feel like taking a nap most afternoons. I get up at 5 a.m. to exercise—but really, should I feel this tired at 3:00 p.m.?”


Athletes commonly complain about fatigue and feeling too tired, too often. Granted, many of them wake up at early to run, attend a morning spin class, or row with the crew team. Some do killer workouts that would leave anyone feeling exhausted. Many routinely get too little sleep. And the question remains: How can I have more energy?

Vitamin pills will not boost your energy. Vitamins help convert food into energy, but they are not a source of energy. Save your money.

Adequate sleep, however, will indeed boost your energy. Sleep is essential to recharge your body with the rest needed to feel fully functional and perform well. Eating the right foods at the right times is also energizing and fights fatigue.

The combination of adequate food plus adequate sleep not only sharply reduces fatigue—but also the need for caffeine. In particular, the late-afternoon cup of Joe that contributes to the bad cycle of sleeping poorly at night, snoozing through breakfast, under-fueling during the day, and fighting chronic fatigue during the day. Sound familiar?

If you feel too tired, too often, you might want to learn from this case study. Tom, a 45-year-old hard-core gym-rat met with me because he wanted to have more energy, eat better, and ideally lose a few pounds of excess body fat. Here is his spreadsheet for a typical day of food and exercise:

Time Food-Exercise Calories
5:00 am Mug of black coffee 0
5:30-6:30 Exercise x 1 hour (- 600)
7:30 Protein bar + banana 400
8:30 More coffee 0
9:30 Small packet almonds 100
Noon Salad/chicken/dressing 500
2:00 Piece of fruit 100
3:00 Iced coffee with milk 100
3:00-5:00 Tired, unable to focus
5:30 pm Gets home “starving”
Active part of day Calories eaten during active part of his day Only


Ideal pre-dinner Ideal pre-dinner intake

for less fatigue

All day Total calories needed 3,000


No wonder, when Tom got home from work, he felt starved. He had consumed less than half the calories he deserved to have eaten for the entire day.

Three ways to fight fatigue

Here are three suggestions I gave Tom to fight fatigue:

#1.  Eat a substantial breakfast and lunchplus a second lunch.A second lunch at 3:00 or 4:00 boosts afternoon energy. It does not add extra calories; it’s just trading evening snacks for a healthy afternoon meal. You are better off eating those calories at the proper time of day, when you need the energy, and not before bed.

#2. Limit caffeinated beverages. Little is wrong with enjoying a morning cup of coffee, but a lot is wrong with abusing coffee to keep you alert in the afternoon. Eat food for true energy, not caffeine, for a stimulant.

#3. Make sleep a priority. You might not be able to go to bed earlier every night, but maybe every other night?


Making a calorie spreadsheet

Most athletes have no idea how much food is appropriate to eat at Breakfast, Lunch #1 and Lunch #2. No wonder they are tired all the time! Many think a yogurt for breakfast, salad for lunch, and an apple for a snack is appropriate. That’s only 700 to 800 calories — way too little!

The best way to estimate your calorie needs is to meet with a local sports dietitian (use the referral network at For a reasonable estimate, add together these three components of your daily energy needs:

            Resting Metabolic Rate (RMR)   Weight x 10 calories/lb.

            Calories for daily life:  30% to 50% of RMR

            Calories for training: ± 400 to 600 cals/hour


Sample energy needs for Tom, who weighs 180 lbs:

1,800 calories to stay alive (RMR; 180 x 10 cals/lb)

600 calories for desk job/light activity (33% x 1,800)

600 calories for hard training for an hour

3,000 calories /day to maintain weight. 2,400-2,600 to lose weight

Target intake: 600-800 calories every 4 hours


Tom started eating:

Breakfast: a banana pre-exercise; then refuel with bagel + PB + latte

Lunch #1 at 11:00:    Soup + sandwich

Lunch #2 at 3:00:      Graham crackers + peanut butter

Dinner: smaller meal that contributed to better sleep.

After just one day of eating enough food at the right time, Tom commented, “I feel great!!! I have more energy and less fatigue…”

Food is indeed a powerful energizer.  Give it a try?


Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875), where she helps both fitness exercisers and competitive athletes create winning food plans.

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