The Warm-up: Why is it always so hard?

Do you ever start a run feeling sluggish and out of breath? A slow pace is difficult and you're uncomfortable even though you think you should feel great because you just started your run?

This happens to me almost every time I go out. I always knew that after I warmed up I would feel better, but I never really knew why I felt so crappy at first. This post actually explains WHY that happens and what is going on inside your body during this warm-up phase of your workout. So the next time you want to turn around and forget the run all together you can remember you’re not having a bad day, your body just needs a little more time to catch up!

The Warm-up Process: Physiologically

When you first start physical activity, your body is utilizing the phosphogen system and anaerobic glycolysis to generate energy rather than the aerobic system. These systems are used because they generate energy more quickly and they do not require the presence of oxygen to create energy. This is good because when you first begin exercising, your body is in oxygen deficit, which is why many people (myself included) find the beginning of their warm-ups to be very uncomfortable.

During this beginning phase of exercise, your body’s sympathetic (“fight or flight”) stimulation increases having widespread effects on your heart rate, blood pressure, and metabolism. Even though many people think this “fight or flight” response only happens when you’re scared, it is actually what causes your body to adjust to the increased demands of exercise. So now your body begins delivering more blood to your active muscles and less to other parts of your body, while simultaneously increasing overall blood flow by increasing your heart rate and stroke volume (the amount of blood pushed out of your heart to your body). These bodily responses mean more blood; and more blood means more oxygen, and more oxygen means more energy!

Once your cardiorespiratory system has fully responded to the fact that you’re now exercising, a level of oxygen consumption high enough to meet the demands of your working muscles is achieved, and you reach a comfortable steady-state of exercise that can be sustained for 30 minutes or more.

So now you know! Don’t stop when you feel like crap at first, give your body 5-10 minutes to catch up with your ambitions and keep on running.

Cedric X.Bryant - Daniel J.Green - American Council on Exercise – 2010

 Fox E, Bowers R, Foss M. The physiological basis for exercise and sport. 5th edition, chapter 3 https://www.cdc.gov/nccdphp/sgr/pdf/chap3.pdf