Why runners should swim part 2: It’s a darn good workout

By Paul Hayes

The aerobic benefits of swimming are, in my opinion greater than or equal to those of distance running. When I was in high school, I constantly had to transition between swimming and running every time the seasons changed, summer included. Every time swimming ended and I started running, my lungs and cardiovascular fitness were great; the most noticeable part of the transition was running with leg hair stubble growing back. But when I finished a track season and hopped back into the pool, I could barely swim 100 yards before I had to stop at the wall to catch my breath, frustrated at my fatigue.

I’ve tried to put some research into VO2Max levels of swimmers and runners, but unfortunately haven’t found anything conclusive. For those who don’t know, VO2Max is how much oxygen an athletes lungs can take in under physical stress, or basically how efficient your lungs are. Studies that have been done show that swimmers generally test lower than runners for VO2Max, but those tests are done by putting a runner on a treadmill with an oxygen sensor mask and running them to fatigue, and then also putting a swimmer on a treadmill and running them to fatigue. For obvious reasons, this isn’t a fair test, and the unfortunate reality is that getting an oxygen sensor mask on a swimmer as they push to fatigue in their own sport seems pretty impossible because that technology doesn’t mix too well with water or the motion swimmer’s need to breathe.

What I can say about oxygen consumption and aerobic capacity from my own experience is that swimming hard takes a lot more than running hard, primarily due to the limited opportunity for oxygen intake that swimmers get. When I run a max-effort race, I talk to the people that finished around me, say good race, make friendships that last about as long a snapchat, whatever. When I swim at max-effort, I’ve found myself so far into oxygen debt that I can’t speak, and tend to just shake hands of the guys next to me, who are also gasping for that delicious air.

What I was able to find is that swimmers and runners tend to have very similar resting heart rates, both in the 40-60 range, with averages around 55. RHR is a good measure of cardiovascular fitness, as it indicates how efficiently your heart works at getting blood where blood needs to go. So the quick conclusion is that swimming and running have similar effects on the cardiovascular system, an important part of any endurance sport. So swimming is a great aerobic/cardiovascular workout.

Additionally, swimming can provide some great anaerobic work, and can help build muscle, especially in some places that are difficult to target. This Website shows all the different muscles that can be used, with names and videos of what gets activated in each of the four strokes. I’m going to break this down a lot more in an upcoming post, but the basic takeaway is that swimming is a workout for nearly all muscles, including the running ones (especially the core, if you do it right). What muscles get worked and how hard really depends on how you swim though, which is what I will be addressing in the next post. But pretty much everything is available for work in the water.

So if you want a workout that taxes your cardiovascular, aerobic, and muscular system while at no impact to your body (no risk of stress fractures, shin splints, or other common running/overuse injuries), I think you should hop in the pool. I also think it’s a lot of fun, but maybe that’s just me.