Here's What Happens If You Don't Warm Up Before Exercising

Hint: It's not good to go from zero to 100 real quick.

Trainers explain what happens if you don't warm up before exercise.

When you want to get in and out of the gym fast, the idea of skipping your warmup can seem pretty enticing. Why walk on the treadmill or do dynamic stretches for 10 minutes when you can simply dive into your workout? Though you might want to get right to the good stuff, experts say it’s super important to take the time to prepare your body before you run, jump, or lift.

The whole purpose of a warmup is to gradually increase your heart rate while bringing blood flow to your muscles, says Katie Pajerowski, PT, DPT, a doctor of physical therapy with Ascend Physical Therapy & Wellness, which is an essential step if you’ve been sitting all day. A warmup also prepares your neuromuscular system, she tells Bustle, and it gets your muscles, joints, and ligaments ready to move through their full range of motion.

That’s why group fitness classes always start with a warmup instead of going from zero to 100, and also why athletes have a dedicated pre-game routine. Even if you’re doing something more low-key, it’s worth it to treat your muscles and joints with the same care.

“By taking the time to warm up, you're doing your body a big favor and ensuring that you'll be able to have a safe and effective workout,” says Lalitha McSorley, PT, a physical therapist and personal trainer at Brentwood Physiotherapy Calgary. “So don't skip the warm up — it's an important part of any exercise routine.” Read on for the risks you face when you work out without prepping your body beforehand.

What Happens If You Don’t Warm Up Before Exercise?


Let’s say you set off down the street for a run without warming up or start lifting weights the moment you get to the gym. While you might be perfectly fine, especially if you take it easy, there are a couple of other potential outcomes to working out cold.

For one, you put yourself at a higher risk for injury, McSorley says, since your muscles and joints aren’t prepped for activity. And this could result in a muscle strain, Pajerowski adds. “Warming up isn't just about getting blood flow and motion to muscles; it's also about the messages that your nerves are sending to your muscles,” she says. “Challenging movements — like doing a box jump or lifting a heavy weight — require a high degree of coordination from your nerves and your muscles.” Warming up is an opportunity to practice that coordination at a lower intensity, she explains, while sending a little wake-up call to the aforementioned neuromuscular system.

If you skip a warmup and dive directly into your routine, chances are you’ll feel cramp-y, creaky, and not so great, says Helen O'Leary, a physiotherapist and director at Complete Pilates. Not only is it uncomfortable to cramp, but it’ll also slow you down so you don’t perform at your best — which means you can’t make the most of your workout. While O’Leary says you will eventually warm up as you get moving, the slow start isn’t ideal when you’re trying to run at a certain pace, play a sport, or keep up in spin class.

How Long Should You Warm Up?


To ensure you don’t get injured or feel crampy, it’ll help to build a 10-minute warm up into the start of every exercise routine. “During this time you should gradually increase your heart rate and loosen up your muscles,” says McSorley. Start off with a brisk walk, jog, or take a spin on a bike and aim to get your heart rate up to about 60 to 70% of its maximum. It’s a good sign if you start to break a sweat since that’s how you’ll know you’re in the right range and are doing enough to get your body warm, says McSorley.

Once you break a sweat go ahead and add in a few dynamic stretches like lunges, squats, arm circles, and neck rolls. These moves will get your muscles and joints ready for a variety of activities so that you can have a safe and effective workout, McSorley says.

You could also take it to the next level and tailor your warm up to the activity you’re about to do. Before a run, McSorley recommends moves that’ll warm your lower extremities, like squats, leg circles, or a walk. If you’re about to work your upper body, she points to machines like the air bike or elliptical as great warm-up machines since the full-body pedaling motion will ensure your legs, torso, and arms are ready to work. Finish with a light stretch that focuses on the muscles you want to train, and you’ll be good to go.

The Bottom Line

A warm up doesn’t have to be all that time-consuming. “When it comes to warming up, many people end up on extreme ends on the spectrum — either they skip the warm up entirely or they feel pressured to perform an overly complex warm-up routine that ultimately has a time cost, which may not be sustainable,” Pajerowski says. “Keeping a warm up simple and accessible is one way to make sure you’ll do it more consistently.” Pay attention to how much better you feel — and perform — in your workouts after prepping your body, and you might just be convinced to take that extra time before every sweat session.

Studies referenced:

Andrade, D. (2015). Effects of general, specific and combined warm-up on explosive muscular performance. Biology of Sport, 32(2), 123-128.

Fortin, F. (2019). Blood-Flow Restricted Warm-Up Alters Muscle Hemodynamics and Oxygenation during Repeated Sprints in American Football Players. Sports, 7(5).

Herman, K. (2012). The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review. BMC Medicine. BMC Med, 75 (2012).

Park, HK. (2018). The effect of warm-ups with stretching on the isokinetic moments of collegiate men. J Exerc Rehabil. doi: 10.12965/jer.1835210.605.

Stewart, I.B. (1998). The effect of warm-up intensity on range of motion and anaerobic performance. J Orthop Sports Phys Ther. PMID: 9475139 DOI: 10.2519/jospt.1998.27.2.154

van den Tillaar, R. (2017). Effects of Short or Long Warm-up on Intermediate Running Performance. J Strength Cond Res. doi: 10.1519/JSC.0000000000001489.


Katie Pajerowski, PT, DPT, doctor of physical therapy with Ascend Physical Therapy & Wellness

Lalitha McSorley, PT, physical therapist, personal trainer at Brentwood Physiotherapy Calgary

Helen O'Leary, physiotherapist, director at Complete Pilates