When was the last time you bounced out of bed, ready to tackle the day? If the answer is “I can’t even remember,” perhaps you could use a rest day. That’s right—a day without a workout. “Anytime we’re training or being physically active, it adds strain to the body, so we need to balance that activity with rest,” says Alana Myers, MS, CPT, an ACE-certified personal trainer and health coach. “That makes it essential to listen to your body and take a day off every few training days.”

Physically, a rest day gives your muscles time to repair, rebuild, and refuel, helping you come back even stronger, says Myers. But if you’ve been going hard to reach your goals, the idea of taking a day off can be difficult to wrap your head around. However, without sufficient downtime, you could risk overtraining, burnout, and injury. 

It might be helpful to know that taking a rest day doesn’t have to mean solely lounging around on the couch. Rest days are about slowing down, not coming to a grinding halt. “This can look different depending on the individual,” says Myers. “For most people, active recuperation will help them recover faster and more efficiently than passive recovery.” Think walking, yoga, stretching, or a leisurely swim or bike ride. However, if you’ve been training intensely and can’t seem to bounce back, an activity-free day may be a better option.

Fitbit’s Daily Readiness Score aims to take the guesswork out of when you need a rest day by providing helpful insights. This metric uses a combination of heart rate variability, activity, and sleep patterns to determine if your body is up for a challenge or if you’d benefit from a little extra recovery time.

At the same time, listening to your body can provide other helpful clues, like these:

You can’t get motivated. “Usually, the first sign is feeling you need more rest or are lacking your usual motivation to work out,” says Myers. Think of this as your brain’s way of letting your body know it’s time to slow down.

You have muscle aches that won’t quit. Some post-workout soreness is completely normal. But if it lingers for days, your muscles may be trying to tell you they need more time to recoup. (Ditto if your legs feel heavy and sluggish when you work out.)

You can’t get a good night’s sleep. “Sleep recharges your batteries, facilitating tissue repair and pain elimination,” says Jacob Teitelbaum, MD, author of Fatigued to Fantastic. In moderate doses, exercise does good things for sleep, helping you nod off more quickly and snooze more soundly. But too much physical activity can interfere with the quality and quantity of sleep, robbing you of these benefits.

Appetite changes. “When someone is overtraining, the body is overloaded and unable to recover appropriately,” says Myers. “This can alter hormone levels that control appetite and satiation signals.” In your body’s quest for fuel, you may start craving sweets, carbs, or salty foods. Or, on the flip side, you may find you have little appetite at all.

Rather than waiting until you’re totally wiped to recoup, try planning a weekly day or two of rest in advance. Skip the alarm clock and sleep in. Silence your phone or leave it in the other room. “And be sure you’re only doing things that feel good to you,” says Teitelbaum. The bills, paperwork, and laundry can wait for another day.