A 2010 study revealed that a decrease in T explained much of the loss in phase III and IV sleep, or "deep sleep" that is characteristic of aging males.  At age 50, men spend 5-7 percent of their sleep time in Phase III and IV and by age 60 it is nearly zero or nonexistent. Young men, on the other hand, spend 10-20 percent of thier total sleep time in these stages due to neuronal integrity and abundant testosterone levels..
The results show that the group that received testosterone scored significantly lower than the group that received the placebo, on average answering 20 percent fewer questions correctly. The testosterone group also “gave incorrect answers more quickly, and correct answers more slowly than the placebo group,” the authors write. The same effect was not seen in the results of the basic math tests administered to both groups. The results “demonstrate a clear and robust causal effect of [testosterone] on human cognition and decision-making,” they conclude.
Having a kettlebell is essentially halfway to having all the exercise equipment you need. From swings to deadlifts, presses, cleans, snatches and goblet squats, grabbing a kettlebell can help you unlock a near-limitless amount of full-body exercises that can string together a monster HIIT workout. If you plan to purchase just one, our advice is to chose a weight according to an exercise that you might find more challenging. You want a KB that's heavy enough to tax you with moves your efficient with but light enough that you can still move it without compromising your form.
$ for a 17-pounder at