After a hard day, you might be tempted to hit it hard in the gym, to release your stress and get your endorphin’s going. But, stressing your body during your workout may be causing you more harm than good. It all depends on how long you’ve been stressed out and what exactly is stressing you.

If you have a fairly low or moderate stress life, but you’ve experienced a stressful day, a high intensity workout is within reason and may provide overall benefit. On the other hand, if your lifestyle is chronically stressful, you can still exercise, but it’s not recommended to set intensity high.

Here’s why:

Chronic stress means you’ve been stressed over time. Keeping your body in a high stress state throughout a workout causes your body to stay in a non-fat burning mode. Those higher stress levels mean there’s also a higher hormone called cortisol. Cortisol breaks down sugars stored in your liver and muscles and dumps them into your blood stream for energy. This is what causes the fight or flight reaction, allowing you to run faster or increase your strength for a short period of time. This type of burst or acute stress can be beneficial for momentary gains, but again, causes your body to remain in a non-fat burning mode.

If you’re stress levels are high consistently, you’re in a fat-store mode; your main objective should be to lower your cortisol levels. Performing low steady state walking is a good option for you. You won’t feel the pump, but you’ll allow your body to decrease stress levels and put you back in a fat-burning mode. The goal is to stimulate fat burning with exercise, not just burn through calories.

If stress is only experienced acutely, don’t be afraid to hit it hard in the gym. If you’re in doubt, talk it over with your trainer and make sure your plan is reaching your long term objectives.