Ask The Trainer: Why Have I Lost My Endurance During Exercise?

The full question asked is as follows:

"I've been working out for the past three months. For the first 2 months, I basically just did the treadmill 45 min./daily x 5 days.

Now I've changed it to 45 min - an hour cardio/strength training classes 4-5 x week plus 2 x wk ab classes. Recently (the past week) I have lost my endurance to keep up with the class.

Yesterday, I worked the treadmill and was wiped out in 12 minutes!! I'm not sure whats going on. Do you?"

Answer:

First of all congratulations on sticking with a workout program for 3 months! You've made a great start on the path to health and fitness. There are a few possible causes for the lack of energy you're experiencing during your workouts.

One thing to look at would be your diet. Has your diet changed since you started working out? Does it need to change? When you're working out regularly your body becomes more sensitive to the quality of your diet. Your body needs the right amount of calories and nutrients to support the increase in activity. Low energy during workouts may be a sign that you're not eating enough carbohydrates.

Getting proper rest is also very important. Are you getting a full night of quality sleep every night?

Lastly, I would want to make sure that your workouts aren't in conflict with eachother.  I'm not sure from the way you wrote it whether you're alternating cardio and strength training clases or if you're doing a combination cardio/strength training class. If it's the latter then you may not be giving your muscles enough time to rest. The rule of thumb for strength training is that you should not strength train the same muscle groups on consecutive days. In other words, if you train chest and back on Monday, don't strength train them again until Wednesday. If you're alternating cardio and strenth training classes then make sure the strength training classes are not on consecutive days.

With  that said, although I can't know for sure without more information, my hunch is that the decrease in energy is related to diet. It sounds like you're making some really positive choices with your exercise. Focusing in on diet will complete the picture.