The importance of a cooldown

So, you warmed up and then had a great work-out. You may feel exhausted and may even be tempted to skip the cooldown and get on with the rest of your day. After all, you’re busy! What’s the big deal about a cooldown? In the previous post, we looked at why it is important to warm up. Let’s briefly review what happens during exercise: breathing and heart rate speed up; blood starts goes to the working muscles; systolic blood pressure may increase to between 160 and 220 mm HG; blood flow increases and gets partially diverted to the working muscles; body temperature increases; muscles contract, especially during strength training; neurons are working hard to send messages throughout the body; and many other actions are happening to adjust to the increased work. Just as the warm-up prepares your heart and the rest of your body for the work that is about to begin, the cooldown helps bring your body back to its normal, stable internal environment.

Suddenly stopping exercise can be dangerous to the cardiovascular system (heart and lungs). Since the blood flow has been diverted to the working muscles, especially during HIIT and strength training, an abrupt stop can mean blood collecting in the legs less blood going to your brain, which can result in feeling dizzy, or even fainting. A 5-10 minute cooldown helps the body adjust heart rate and breathing, body temperature, oxygen and blood flow, and blood pressure in a safe, gradual, manner.

During exercise, lactic acid is produced by the body. An active cooldown helps facilitate moving out the excess lactic acid. This process also helps blood sugar levels to adjust safely after exercise through gluconeogenesis. Additionally, other hormonal changes take place during exercise that a cool down can help level out post-exercise.

How do you cool down?

There are two types of cool downs: active and passive. An active cooldown and a passive cooldown. An active cooldown take place within an hour of the workout. It is a light-to-medium intensity movement. Examples could be a slow walk (outdoors or indoors), a slow march-in-place, etc. The idea is to have a lesser intensity than was maintained throughout the workout, in order to bring the body back to homeostasis. Another idea could be walking in a pool, after an intense swimming session. An example of a passive cooldown is static stretching. Other examples could include foam rolling, hot/cold water immersion, and vibration therapy, among many others.

Since stretching is one of the most recognizable cool downs, let’s discuss that one. As previously mentioned, the muscles contract during exercise. Static stretching (holding a stretch, usually between 15 and 60 seconds) can help lengthen those muscle fibers. Static stretching should be done when the muscles are warm, so the cooldown is a perfect time. Stretching can help promote blood flow, may alleviate some DOMS (delayed onset muscle soreness), reduces stress, helps promote muscle balance (which may prevent injury), and improves posture.   

Resources:

Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association joint position statement. Diabetes Care. 2010;33(12):e147-e167.

Greenwood JD, Moses GE, Bernardino FM, Gaesser GA. Intensity of exercise recovery, blood lactate disappearance, and subsequent swimming performance. J Sports Sci. 2008;26(1):29-34.

Pesova, P.; Jiravska Godula, B.; Jiravsky, O.; Jelinek, L.; Sovova, M.; Moravcova, K.; Ozana, J.; Gajdusek, L.; Miklik, R.; Sknouril, L.; et al. Exercise-Induced Blood Pressure Dynamics: Insights from the General Population and the Athletic Cohort. J. Cardiovasc. Dev. Dis. 2023, 10, 480

Van Hooren B, Peake JM. Do We Need a Cool-Down After Exercise? A Narrative Review of the Psychophysiological Effects and the Effects on Performance, Injuries and the Long-Term Adaptive Response. Sports Med . 2018 Jul;48(7):1575-1595.