Shivering caused by dehydration, however, is not why you should push yourself. “If you’re shivering due to dehydration, stop exercising, drink water or an electrolyte drink, and seek medical attention if necessary,” Goodtree says. If you feel tired, dizzy, light-headed or thirsty, or have dry skin and lips, muscle cramps or a headache…general features3 dehydration is your cue to pause your workout and rehydrate.

While shaking during exercise isn’t always a red flag, you shouldn’t aim to shake either. “As a fitness professional and personal trainer, I don’t think ‘making your muscles tremble’ is an effective goal,” says Goodtree. Instead, set SMART (Specific, Measurable, Attainable, Relevant, and Time-Bound) goals for your fitness program, she suggests. For example, a person who is not yet able to do full push-ups can set a goal of doing 10 push-ups on their toes within two months. “To achieve this, you can work on chest presses, overhead presses, planks, and shoulder mobility,” she recommends. “You might feel some muscle tremors along the way, too!”