your nipples most likely become erect during exercise as part of the thermoregulation process of maintaining your body’s internal core temperature or as a result of other stimuli. there doesn’t seem to be a clear agreement for the physiological response that is taking place during exercise specifically but here are a few ideas: • your body heats up during exercise and it produces sweat as a response. your sweat evaporates from your skin removing heat and cooling your body in the process. your nipples can become erect as they are being cooled since coldness is a stimulus for erect nipples. • exercise shirts are designed to be “breathable” by increasing circulation to disperse heat away from your skin. this increased airflow and circulation could compound the cooling effect of evaporation. • your nipples are very sensitive so the continual friction caused by your shirt vigorously moving back and forth as you exercise may be irritating them. • your body may just be at a heightened state of arousal during exercise. this doesn’t mean sexual arousal rather just a physiological state of heighted autonomic arousal that you experience during exercise in the same way that you experience changes to heart rate respiratory rate perspiration etc. erect nipples may just be another natural component of that. try to take notice of when you first experience this happening so that maybe you can better identify what’s triggering it. if it bothers you i would suggest wearing a padded exercise bra if you’re a woman or experiment with different clothing materials for your shirt. try putting your exercise shirt as a base layer and a cotton t-shirt over it to help keep you warm and to cover it up. you can also buy nipple covers or put a band-aid over them to help conceal them.
why do nipples get hard during exercise? . i'm not cold when i exercise in the gym but my nipples are always erect. what is the physiological response that's taking place?