A couple of observations. First a question. Is this guy a medical doctor, PhD or a Chiropractor? I can't find out through a quick look of his site.
1. Looking at his head shot he is a chubby guy. When I went to an endocrinologist he told me a good way to increase testosterone is to get lean. Could it be his problem with low test?
2. He cites a study I believe around the 9 minute mark that says a whopping 64 miles a week of running lowers testosterone. Holy shit, 64 miles! Personally I never go over 20 miles a week at this age which really isn't relevant to this conversation. I would agree that doing an insane amount of cardio like the study cited can lower testosterone. On another related topic Doctor Cooper that coined the phrase Aerobic exercise and studied cardio for over 50 years said anything over 15-20 miles a week returns less health benefits showing a bell graph into longevity from lowering risk factors for good health. In the video Ironat put up he says 150 minutes a week of cardio is good for your health.
3. He mentions but never explains that over training can affect females showed through a lack of a monthly period. Females need a certain fat level to have a period and when they get too lean they have that problem. Yes, a certain amount of fat is needed for good health in females.
4. He blames volume weight training for his low test though he admits finding studies for that are hard to find. He was doing volume six days a week. Without using steroids any natural would have problems with that kind of extreme.
My empirical thoughts on this. Cardio for me improves my libido. Doing too many miles can decrease it. What's the number of miles for a runner? Can't give a definitive answer but his study showing a whopping 64 miles a week illustrates the extreme he is talking about.
Regarding weight training. Since I don't use steroids or so called hormone replacement, training naturally, you need rest. Even though I generally use split training I know training the whole body in one session then taking off a day or even up to three days between is a great weight training strategy for most naturals. Your body fatigues as a unit and fatigue isn't just localized in the body part trained.
If you use a split some general guidelines for most is to hit a body part directly once a week to twice for a natural. No way around it if you use a split you have over lap in training body parts. What I mean is when you are doing any pressing you are also training triceps. Doing any pulling you're using biceps. On back day with with deadlifts or say power cleans you are using legs. I say this meaning that even if you hit a body part once a week with a split you are not hitting a body part once a week.