They say too much of a good thing is bad. Well, cardio isn’t even a good thing. I mean, it is, but it’s just not fun. Let’s be honest, it kind of sucks. Every time I go for a run, the entire time I just think to myself “this sucks, this sucks, this sucks, ugh when can I be done!?”
Well, I have good news! Too much cardio is actually bad for you. So now everyone who wants to slack on their cardio (ahem, me) has a justified reason to do so. Allow me to explain.
Everyone knows that cardio can be extremely healthy for you. It has implications in fat loss, cardiovascular health, longevity, and can even prevent the common cold (O’Keefe et al., 2012). The American College of Sports Medicine suggests 20 minutes of vigorous cardio, 3 times a week. Up that much more, and you’ll be focused on weight loss. But if you increase that even more, some real bad things are gonna start to happen.
Scientists have shown that excessive cardio routines can cause a complete restructuring of the heart and large arteries, directly affecting cardiovascular health in the opposite way that these exercises intend to (O’Keefe et al., 2012). This is especially true in the right ventricle, the part of the heart that is responsible for pumping oxygen-poor blood to the lungs (La Gerche et al., 2011). This blood releases carbon dioxide and picks up oxygen, and is integral for proper respiration. Problems with this part of the heart can lead to congestive heart failure. Did you hear me? I just told you that excessive cardio = heart failure.
Have you heard of cortisol, the stress hormone? Yeah, I’ve seen the popular videos about it, too. How does that relate? Well, prolonged aerobic exercise can up the amount of cortisol in your body, sometimes by more than 54% (Kindermann et al., 1982). But cortisol isn’t just a stress hormone, it’s intricately involved with blood pressure and metabolism, and an excess of cortisol can lead to obesity, insulin resistance, and diabetes (Fraser et al., 1999). In simpler terms… too much cardio means too much cortisol, which impacts fat storage. Instead of helping with weight loss, prolonged and excessive cardio can actually lead to weight gain.
I have even better news: scientists have officially ruled that high-intensity interval training (known to most as HIIT) improves oxygen intake and cardiovascular health much more efficiently than typical cardio routines (Helgerud et al., 2007). This was backed by another study that ruled it is intensity, not duration, of aerobic activity that truly counts (Schnohr et al., 2012).
So…”HA!” to all those people who criticize me and gasp when I tell them I do minimal cardio. And to all those who are wondering how to lose weight if too much cardio isn’t working, try weight-lifting. I know it can be intimidating the first time you step foot in that room, but if you want results, consider this: lifting builds muscle, and the metabolic rate of skeletal muscle v.s. adipose tissue (aka fat) at rest is 13 to ~4 (Wang et al., 2010). So, if you really wanna burn more calories and lean out, your best bet is to introduce some HIIT to your workouts and lift them weights!