It’s normal to be out of breath, feel slight muscle strain and have an elevated heart rate during exercise. What’s not normal is a rapid heart rate accompanied by dizziness and shortness of breath followed by tightness in your chest or acute pain followed by loss of strength or stability.
These are all signs that you should stop your workout immediately, and we turned to the pros, from doctors to personal trainers and exercise physiologists, to find out why. Keep the following warning signs in mind if something feels abnormal during your next workout.
1. Your heart rate spikes higher than normal
The cause could be as simple as dehydration or as complex as an abnormal heart condition.
Heart rate monitors and fitness trackers help you work your hardest, allowing you to track heart rate, and therefore exertion, during the workout. Your tracker is also a great tool to make sure everything is going OK during exercise:
“If you’re wearing a fitness tracker and notice your heart rate spiking abnormally, especially beyond your max heart rate and not normalizing after stopping for rest between sets, stop immediately and seek help,” suggests the owner of TrapFit with Tini.
To stay aware of this potential issue, you need to know your max heart rate and average heart rate during a normal workout. Start by finding your max heart rate, which you can do with this calculation: 220 minus your age.
While not 100 percent accurate, it provides a good baseline. Then make note of your heart rate during three workouts that represent a normal training session for you.
Now you know what your max heart rate should be in addition to what you average in regular conditions. This way, you’ll know if the numbers fluctuate extremely. Call your doctor immediately if notice any abnormalities.
2. You feel faint, confused or dizzy
The cause could be low blood sugar, otherwise known as hypoglycemia. This can happen if/when you work out on an empty stomach.
You’ve probably heard mixed opinions on eating before working out from those who promote fasted cardio to the professionals who recommend eating at least 1 to 2 hours before exercise. If you choose to work out before eating, pay attention to potential bodily cues telling you to stop, says Dr. Nina Watson, Certified Diagnostic Radiologist, with expertise in women’s wellness, fitness and nutrition.
“If during your workout you begin to experience unusual tiredness, shakiness, racing heart rate, that progress to the point where you begin to feel like you are going to pass out or are confused, and you have changes with your vision, it’s time to stop your workout immediately,” says Watson.
If you know you haven’t eaten yet today, or in a few hours, your first step is to eat something small, high in sugar and carbohydrates, like a banana and peanut butter, an apple with cheese or a juice box. If you still don’t feel better, see your doctor or a health professional.
3. You feel a sharp pain in your joint
The cause could be an injury or tear in your joint, muscle, tissue or ligaments.
If you feel a sharp pain in a joint that’s followed by a decrease in strength or stability or sudden swelling, it’s time to stop, suggests Vivian Eisenstadt, MAPT, CPT, MASP, orthopedic physical therapist and personal trainer. She explains, “This usually means you have torn something or have injured yourself. Continuing to work out on a newly injured unstable joint can make it much worse. Stop immediately, ice and assess it.”
See a doctor as soon as you can to determine the extent of the damage. Avoid putting pressure, on the area, even as you rest or walk around at home, until you know what happened.
4. You reach technical failure on an exercise
The cause is likely that you’re tired and it’s time to rest.
It’s critical that you always perform your exercises with the correct form. When you become fatigued, however, form is often the first thing to falter, which is what Bruce Kelly, MS, CSCS, NASM-PES, FMS, means by “technical failure.” He explains:
“When your form/technique is not good, stop the set/exercise. Nothing good will come out of what follows. You are either inviting injury, at worst, or ingraining poor motor/movement patterns which may not be injurious immediately but leads to problems down the road.”
The key is to listen to your body. Tanya Otterstein-Liehs, owner of Body Business, shares a few technical failure signs to look for:
- When performing a bicep curl, you use your back/shoulder to throw the weight up and perform the curl.
- When you sink your glutes back and down to perform a squat, but your chest falls forward and your knees are moving forward, going past your toes.
- When you’re doing a sit up, and you’re no longer engaging your abdominal muscles to curl up, but instead, are pulling on your neck muscles and back to curl up.
Working when fatigued to this point could lead to injuries or strained muscles, so stop and resume another day when you’re ready to keep proper form.
5. You feel any signs of heart trouble
The cause could be a wide range of issues, from an oncoming heart attack to poor digestion.
When working out, there are a number of signs that tell you to stop because of potential issues with your heart. Jeremy Kring, MS, CPT, CSS suggests these signs include, but are not limited to:
- Chest pain
- Excessive rise in blood pressure (if you have wearable that tells you the blood pressure) that is >250 mmHg systolic or >150 mmHG diastolic.
- Shooting pain in left arm
If you feel pain or discomfort, Sheri Traxler, M.Ed. suggests taking the following steps: “Stop. Evaluate if it is cardiac or digestive issues. If other signs/symptoms or severity indicate possible cardiac issues, do not resume a workout and get medical help immediately.”
Watch for the signs
Don’t be scared to work out because of potential dangers. Simply knowing what to look for and when to stop is often enough to discover any potential issues before they become a problem. Ask for help from someone in the gym or a person walking by if necessary and consult with your doctor as soon as you can to ensure there are not further problems to be concerned about.
Otherwise, enjoy getting stronger and fitter with each successful workout and always be aware of what your body is telling you.