Does a swim cap make me faster?

I had a bad morning today. I rode into 2 fences on the way to the pool. I also forgot my swim cap. I have NEVER done this before, and I must confess had a mini crisis when I realised. I NEVER swim without it, how on earth was I going to cope?!?!

So, with no choice but to get on with it, I did the set. I found I was distinctly average. It felt very odd swimming without a cap, and I felt like my stroke was nowhere near as neat as usual. Thankfully I had clips, because with long hair and a fringe, I wouldn’t have seen a thing otherwise!! As I got used to having hair flailing around, I settled down a bit and I think the stroke improved. The whole time though, I was wondering, ‘am I slower because I have no hat?’ So, I set about finding out the answer to this question!

It seems the common thought is a cap reduces drag and therefore makes you faster.

The first article I found says  ‘The difference in drag between a closely cropped head of hair and a cap is minimal at best. Furthermore, that cap acts like an insulator keeping all the heat your head is trying to radiate away from your body, while highly exerting yourself, trapped. Most of a body’s working fatigue comes from the heat generated by the muscles in the act of working’

Short hair?

Seems logical, a man with very short hair probably won’t gain anything by wearing a cap. I hadn’t thought really about the heat thing. I guess this may be an issue for pool competitive swimmers, but as a triathlete, a cap in open water is essential so that’s not really something I will concern myself over.

The article goes on to say that fatigue caused by overheating if you wear a hat, is accumulative, so over a short time you probably won’t notice. It does point out the effect it will have on stroke, something I alluded to when I described my swim session this morning.

Long hair?

Obviously, if you have long hair, and you can’t see because its flowing all around, then it stands to reason that your stroke will be altered, aerodynamics affected, therefore speed will it seems also be affected, if you applied logic to the scenario.

Frictional drag?

There are three main types of drag on a swimmer, Frictional, pressure and wave.

You might also consider the frictional drag of hair, compared to silicone. ‘According to Ernest Maglischo’s book, “Swimming Fastest”, hair is a source of frictional drag.’

Several sources seem to suggest that this could in fact be true:

‘Swimmers often attempt to reduce drag by using swim caps, special suits, and shaving prior to competitions’  

For the same reason that swimmers will wear a body suit, the hair on the body causes drag in the water.’


It seems swimming without a cap could in fact have made me swim slower for two reasons: frictional drag caused by my hair, and altered swim mechanics due to the hair being in my way, rather than tucked under a cap.

Phew, I thought I was just having a bad day, now I can blame the lack of cap (in part at least!)

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