Cardio queens, adrenaline junkies, runners with a constant high and cardioholics, please stand up! (Then sit down. And then plyo jump back up. Repeat down and up until your heart rate is in zone 4.) New research is afoot in the great cardio debate and — I’m going to break this to you gently, so don’t run away — you’re not gonna like it. The skim-worthy version of the no less than six new studies on the subject of cardiovascular exercise, heart health and life outcomes is this: People who do some cardio live longer and healthier lives than people who don’t do any. But people who do lots of cardio have more heart problems and die sooner.

I know. Kinda stopped my heart too. (Har!) Because of course I am a reformed cardioholic myself. (For any newbies, I used to exercise up to 6 hours a day, most of it cardio, and ended up suppressing my own thyroid, gaining ten pounds, losing my freaking mind and ending up in eating disorder treatment for compulsive over-exercise. Plus I got to be the freak of the week on a bunch of TV shows and in magazine articles thereby becoming the de facto cautionary tale in all discussions of exercise bulimia. My parents are so proud!) To this day I’m still an adrenaline junkie and if left unchecked will exercise way more than is necessary.

Confession: This past month since I’ve had unlimited access to all of LifeTime Fitness‘ amazing programs I’ve been working out two, sometimes three, times a day. Take Monday, for example, when I did an hour of weight lifting in the morning followed by two hours of puketastic MMA training that night. Or today with an hour of “no limits cardio” in the a.m. and then 1.5 hours of basketball. Yeah. But unlike previous periods of over-exercise, it hasn’t been in an effort to lose weight or “earn” my food. This time it’s more of a ticking-clock problem: I feel like I have such limited time so I have to do! everything! while! I! still! can! And everything is just so much fun!! This is a problem. I know it. I’m working on fixing it. It helps that LifeTime extended my pass for 3 months so now I have a little more time. But the first step is staying accountable, which is why I’m telling you this. My husband and the Gym Buddies are all fully aware of what I’m doing too (again, unlike last time where I did my best to hide it from everyone). And tomorrow I only have one workout scheduled and then I’m relaxing by the pool with the kiddos!

/End overshare/ Back to the research! The key in all of this is defining what exactly constitutes “too much” cardio. This can vary from person to person but in a study of 14,000 runners and 38,000 non-runners conducted by the Mayo Clinic and the American College of Sports Medicine researchers found some very interesting numbers. So how much is “a lot” of cardio? Not as much as you’d think:

The runners with the lowest death rate were those who ran 10-15 miles/week, only ran 2-3 days/week and kept a pace between 10 and 8:30 minutes/mile. Translate that running into any cardio activity* and you’re looking at 20-30 minutes a day, 5 days a week at the high end. Runners who ran more, or more days, or faster, had higher death rates. Check out the tables of the hazard ratios and you’ll see that jumping up to 25+ miles/week or 7 days/week skyrockets your risk of a negative health outcome.  Runner’s World‘s Amby Burfoot writes, “What this paper points out is that a lot of people do not understand that the lion’s share of health benefits accrue at a relatively modest level… Beyond 30-60 minutes per day, you reach a point of diminishing returns.”