chopping trees causes testosterone to surge

Latest from New Scientist: playing soccer and chopping trees can cause 30% surges in testosterone. It seems the baseline quantity of testosterone is less important than the activity that brings it forth. Also it seems that once you remove depressed and obese men from the smple testosterone drops a negligible amount over one's life. 80 year old men show the same surges - if they are fit- as men in their 30s.