2009 Studies & Research Blog

If one of your main goals for the coming New Year is to participate in a running event, possibly a half or full marathon, it’s a good idea to consider placing your weight lifting focus on the backburner.

That’s not too say you shouldn’t still lift weights – you should, just that you likely shouldn’t expect to make really great gains while doing so.

First off, you need to realize that many of the hormonal responses that occur in the body after prolonged running takes place are going to be ones that will oppose those of strength training and will not work towards helping you add additional muscle mass.

So, right from the start once you begin doing hour long plus running sessions, you’re going to see side effects.

With a proper diet and enough rest you can help minimize muscle loss while doing your training, but it’s rare to see people doing high volumes of cardio while packing on lean muscle tissue at the same time.

Recently researchers looked at the hormone response that took place after a marathon race in non-elite athletes and their findings help to back these points up.

The researchers drew blood samples one week before a marathon race was to take place, immediately after the race was finished, and then one week after the race was finished and recovery had taken place.

The results of the study indicated that the serum cortisol and prolactin were significantly higher in the time immediately after the race compared to before, but returned back down to more normal levels after the week of recovery had passed.

In addition to this, total testosterone as well as free testosterone also dropped significantly, indicating that this would put the body in a position not conducive to building lean muscle mass (since testosterone is the primary hormone that helps synthesize new muscle tissue).  Again, testosterone levels were returned back to baseline one week after the race too place.

So, the take home message from this is that while marathon training and actually running the race will certainly alter the hormonal profile you experience while training, after you discontinue with that training and move on to more moderate cardio sessions your hormonal profile will return back to normal within a short period of time and you should be able to start making gains with your lean mass building once again (assuming a proper diet is also in line, obviously).

Reference:
Charokopos, N, et al. (2008) Hormonal response to marathon running in non-elite athletes. Eur J Intern Med. Dec; 19(8):598-601.