Pro baseball players in balmy Florida for spring training and NFL players in temperature-controlled domes all still go through carefully scripted warm up routines before they train and play. Why, when they’re already sweating? Because warm-up has surprisingly less to do with increasing temperature and more to do with ensuring good performance.

Here are the 5 most important reasons to perform a good warm-up even when it’s warm out. Let’s count down.

#5. to increase the body’s core temperature – Working muscles generate heat which increases the body’s temperature. Warm muscles work more efficiently and effectively. Their cellular machinery cycles through contractile processes more quickly and with more ease.

#4. to increase blood circulation to the working muscles – Body movement gets the heart pumping and the blood flowing to hard-working muscles, delivering nutrients and extracting wastes. These are essential to sustaining performance at a high level.

#3. to increase joint mobility – An increase in body temperature makes the natural lubricants in our joints more fluid and “well-oiled” joints allow us to move more freely and more comfortably. Plus, supple joints can move more easily through a wider range of motion.

#2. to acquaint the body with the field – Proper warm-up introduces us to playing conditions for the day. This allows us to get the “feel” for the ball, the field and the environmental conditions. Experienced athletes use this information to calibrate their skills and adapt them for best performance.

#1. to activate the neuromuscular connection between brain and body – Warm-up revs up the electrical signaling from our brain to our muscles, telling them what to do and how, calling on our memory of what we;ve practiced. Muscles and joints send electrical signals back to the brain so it knows how close we’ve come to executing its instructions. A dedicated warm-up dials us into this brain-body conversation. The better we listen, the more accurately we perform.

So, at every level — from sandlot to World Series, from street soccer to Premier League stadium — warm up wakes the body up, prepares it to perform and tunes it in to today’s channel for today’s contest.

No serious athlete would ever skip warm-up. Otherwise they’d spend the important first minutes of the contest doing what the body must: increasing body temperature, getting the heart pumping, getting the muscles working and the kinks out of the joints. But the #1 reason for every player to warm up is to tune in the brain-body interaction, dialing in that channel so we can perform the way we practiced.

Next time, you’re tempted to skip warm up because “you’ve got so much to do during practice,” don’t give into temptation. It turns us on, tunes us in, and cranks us up so we can let loose with all we’ve got. It’s the on-switch that activates everything else.

Next up: Proprioception, the “movement sense” that’s the secret to performance.