﻿ Ask the Experts: When You're Too Tired to Exercise on MedicineNet.com

Fitness Q&A by Richard Weil

It's hard to motivate myself to exercise, because I always feel tired. I've tried eating a banana before working out, but it doesn't help. How can I boost my energy levels before exercising?


There are many reasons for fatigue. If your energy levels don't improve, with or without a change in your diet or exercise, then you ought to consult with your physician.

If you rule out medical conditions for your fatigue, then the first thing you ought to look at is how much sleep you get. If you wake up after three to four hours of sleep and expect to exercise hard first thing in the morning, then you may be in trouble. Make sure to get plenty of rest when you are on a structured exercise plan.

The next factor to look at is the timing of your meals and snacks in relation to working out. If it has been more than four hours since you've had anything to eat, then even a banana beforehand might not do it. You may need to experiment with timing of your meals and snacks by bringing them closer to workout time, perhaps 45-90 minutes beforehand. Some people try coffee (for the caffeine), fruit juice, or other sugary drinks for energy before a workout, but on an empty stomach, these can upset the gut during hard workouts and the energy effect is generally short-term. Complex carbohydrates (carbs) are usually a better choice, and protein can help, too (see below for suggestions).

Interestingly, complex carbs and protein may not only help with energy, but they may also speed up your post-workout recovery time. Research shows that eating carbs and protein after you work out, but within 30 minutes of completion of a workout, helps speed up recovery time by replenishing glycogen stores and possibly increasing protein synthesis. Glycogen is the stored glucose in your muscles and liver. Although it has not been proven, you could conceivably have more energy for the next workout if you recover faster from the previous one. There is also some evidence that eating protein and carbs before your workout helps with protein synthesis and recovery time, but less is known about this.

The guideline for carb consumption after your workout (within 30 minutes of completion) is to have 0.7-1.2 grams of carbohydrate per kilogram of body weight (0.3-0.6 grams per pound). A large banana has 30 grams of carbohydrate. The guideline for protein is one gram for every three to four grams of carbohydrate. Peanut butter has nine grams of protein per two tablespoons. Yogurt is another good source of carbs and protein, and you can also check the labels on commercially available energy bars. The guidelines for quantity before exercise are not as clear as after exercise, but carbs and protein are part of the equation, so you might want to experiment with the guidelines for after the workout that I just posted. If you have specific questions about snacks, you can send them to Betty Kovacs, the MedicineNet.com dietitian at http://www.medicinenet.com/script/main/art.asp?articlekey=77396.

One other possible cause of fatigue (if it's not medical) is overtraining. Symptoms of overtraining are loss of strength, speed, endurance, or other elements of performance, loss of appetite, inability to sleep well, chronic aches and pains or soreness, chronic colds or respiratory infections, overuse injuries like tendinitis, unusual fatigue, occasional increase in resting heart rate, irritability, or you just don't feel like exercising anymore. If you've been pushing hard without any rest days, then your fatigue could be due to overtraining and you will need to take a break. Most people come back refreshed and stronger after a one to two week break if they have been overtraining.

I hope that helps.

Thank you for your question.

Last Editorial Review: 12/18/2006