For adults, the CDC recommends at least 2 hours and 30 minutes of moderate-intensity aerobic activity and two, or more, days of muscle training per week. However, not everyone meets those standards. This is what happens to your body when you go from regular exercise to none at all.

Following is a transcript of the video, which is largely based on the information in this Gizmodo article.

What happens when you stop exercising? Changes happen over weeks to months. Here’s a breakdown.

Week 1: You’re already less fit. You’ve lost about 5% of your “VO2 max” which means less oxygen is available to generate energy for muscles. If you could run a 5K in 20 minutes, your time is now about 10 seconds longer.

Weeks 2-3: You now have lost 12% of your VO2 max. There's a decrease in muscle strength and tissue. Your muscle cells have become smaller. Your fat cells are getting bigger. Your 5K time is now about 60 seconds longer.

Weeks 4-7: 12-15% loss in VO2 max. Your muscle cells are even smaller. You might feel bloated from growing fat cells. Your 5K time is now 3 minutes longer.

After 2 months: 26% loss in VO2 max. Just stop timing your 5K because it's depressing.

If you keep it up, you'll also be at greater risk of high blood pressure, high levels of fat in the blood, certain cardiovascular diseases, obesity, depression, and low self-esteem.

It's important to rest after an especially hard workout or race. But instead of lounging on the couch, make your recovery an active one. If you just lay around, you'll lose that fitness faster than you think.

This video was originally published on July 17, 2017.