Working out can be uncomfortable. It's a fact. You might even gauge your workout by the level of discomfort. Sore muscles a day or two after exercise are often considered signs of a job well done. After all, reaching for another rep and pushing through another mile is what helps build strength and endurance, right? But how do you distinguish between discomfort and danger? How do you know when your body is telling you it’s not safe to work out? Whether you’re a newbie gym member or a veteran athlete, paying attention to the following warning signs will help you stay safe and avoid injury.
1. You feel sick.
If you’re feeling under the weather, there’s a good chance your body is working hard to fight whatever illness has taken hold. Piling on the stress of an intense exercise session is never a good idea when you’re sick. Working out vigorously with a fever, sore throat, nausea, gastrointestinal distress, or severe aches and pains could make the symptoms worse and potentially result in a longer healing time. If you have any of these symptoms prior to your workout, don’t even start. Wait until you're feeling better and then reintroduce exercise slowly. If you spent a few days or weeks recovering, your fitness level will likely have taken a small hit. Ease back into your routine—avoid the urge to start where you left off. When you get back in the game, go with lighter intensity and shorter duration for a week or two until you feel like your pre-sick self again.
2. Ouch! Something hurts.
Pain is typically the body’s way of signaling a problem so you can quickly address whatever's causing it and protect yourself from further harm. There are two general types of pain: acute and chronic. Acute pain is the result of a single or immediate trauma, like a sprained ankle. Chronic pain is the persistence of pain even after the normal amount of healing time (weeks or months depending on the problem). The low back is a common site for chronic pain.
In terms of exercising, acute pain is always a warning sign to stop. Sharp, intense pain and/or sudden swelling are often associated with acute trauma. Any attempts to push through these sensations during a workout will only exacerbate the problem and delay healing. Chronic pain, on the other hand, is treated quite differently. In fact, physical activity and exercise programs are increasingly recommended for various types of chronic pain. Check with your doctor or health care provider for physical-activity recommendations.
One last thing about pain: Working out may cause myriad sensations (elevated heart rate, rapid breathing, heavy sweating, shakiness and fatigue, and even muscle “burning”). As uncomfortable as these sensations may be, they generally do not qualify as pain and are accepted as part of physical exertion.
3. You're having trouble breathing.
Difficulty breathing could be an indication of a respiratory condition (exercise-induced asthma), a circulatory problem (heart or vessel disease), or an exercise intensity that is beyond an individual’s current level of fitness. A normal response to vigorous exercise is heavy breathing. In fact, exercisers who engage in high-intensity interval training get to that point with every interval. A healthy person's breathing rate gradually returns to normal shortly after the effort ends. However, gasping for air during minimal exertion or feeling like you're unable to catch your breath after exercise is a sign of a bigger problem. If you struggle to breathe during exercise, back off the intensity to see if it gets better. If it doesn’t, seek recommendations from your doctor or health care provider.
4. You feel light-headed.
Feeling dizzy or light-headed could be an indication of a cardiovascular (heart and circulatory), respiratory (breathing), or metabolic (low blood sugar) problem. If you begin to feel faint during a workout session, stop exercise ASAP to avoid passing out. Transition to a comfortable seated or lying position to prevent falling and allow the blood to more readily reach the brain. Seek medical attention if the feeling persists after the workout. It might go without saying, but if light-headedness is a recurring problem, during a workout or otherwise, get it checked out by a physician.
5. You experience chest pain, pressure, or discomfort.
In terms of potential seriousness, this warning sign is the most severe. A cardiac event, such as a heart attack, is relatively rare during exercise. It is most likely to occur in a person with underlying heart disease. The problem is people often aren’t aware they have a heart issue until they experience the warning signs of chest pain, pressure, or discomfort. These are more likely to surface during physical exertion than at rest, so a workout might be the first time these symptoms manifest. Experiencing them during a workout session is an indicator to stop exercising immediately and seek medical attention, as this could be a sign of a potentially life-threatening condition. Interestingly, in addition to chest pain (the hallmark symptom of a heart attack), women, especially, are more likely to have other symptoms, such as pain or discomfort in the back, jaw, or throat, as well as a headache, nausea, and coughing. Paying attention to these symptoms and seeking treatment from a health care professional could save your life.
Ultimately, exercise is still your best bet. Being physically active is an integral part of optimal health and wellness. However, these five warning signs represent rare occasions when exercise should be discontinued until healing and/or medical treatment occurs. Knowing your body, as well as the signs of distress, will keep your workouts safe so you can confidently reap the benefits.
Sabrena Jo is the senior exercise scientist for the American Council on Exercise, where she gets to follow her passion of relentlessly pursuing ways to help people start and stick with physical activity. Follow her on Instagram and Twitter.