“According to a new study” is a phrase that should set your bullshit alarm ringing. Journalists don’t in general understand either the methodology or conclusions of published studies and instead seize on the most lurid parts of the accompanying press release. So, with that in mind, here we go:
According to a new study, cycling a lot can affect your fertility if you are a man. The latest study to suggest this is reported quite well here: Elite cyclists ‘risk infertility’.
The conclusions are sensible: “the average man cycling to work would be unlikely to suffer fertility problems because of their time in the saddle.” and “40 years ago cycling was much more common but there is no evidence men then were less fertile”. So there’s nothing to worry about, right?
Perhaps. Perhaps not. My first son was conceived with the aid of a lot of expensive medical help (IVF to be precise), the reason: poor sperm motility and morphology. My second son was conceived the regular way. The only difference between the two pregnancies was that I’d stopped cycling after the first sperm tests.
My anecdotal evidence has no scientific weight at all but I would suggest the following things may be true:
- 40 years ago saddles were a lot different to now. Lightweight racing saddles give you little room for manoeuvre (men, you know what I mean). A poor posture can lead to numbness and discomfort that lasts most of the day as I have found myself. If this is happening to you then consider the other long-term effects that might also be happening. Sort out your posture.
- A short ride over bad roads (e.g. central London) might inflict damage equivalent to many more miles over a triathlon course. I believe that a modest amount of inner-city commuting might be the equivalent of 186 miles a week of triathlon training.
- If your fertility is borderline anyway then it might take relatively little additional damage to make it noticeably more difficult to conceive.
The conclusions of the BBC article are sensible but do consider the personal risks to you rather than the general statistical results.
Also: none of the studies I’ve seen have ever investigated the effects of stopping cycling. From my own experience this had a positive effect on my fertility, but that’s not science. Please could somebody do a follow-up and investigate this aspect too?
Annoying journalistic habit note
How come the study talks about training amounts above and below 186 miles? Isn’t this a rather arbitrary figure to use for the study?
Yes, but of course the study was from a more enlightened country that uses OSI units for measuring distance. 186 miles is 300 kikometres. So the study drew the perfectly acceptable conclusion that around 300 kilometres a week was an amount that might contribute to infertility.
Converting this to exactly 186 miles is ridiculous for two reasons:
- The original figure is stated to one significant figure. The equivalent imperial distance would be, say, 200 miles a week.
- I am relatively aged, and I remember being taught metric units at school. Why oh why do we have to assume that people only understand our grandparents' units?
Come on, journalists of Britain, most of us are not geriatric or imbeciles.