I was always told as a bodybuilder, to do squats and deadlifts because they increased testosterone and helped build muscle throughout the body. I decided to try and seek out a definitive answer to these common beliefs.
Studies on Testosterone Increase in Squats & Deadlifts :
It didn’t take me too long to stumble across research studies showing that after squats or deadlifts, there was a large increase in serum testosterone levels. Not only is there a increase in testosterone levels, but in Growth Hormone and IGF-1, a couple of other important anabolic hormones. This anabolic release didn’t just happen in squats and deadlifts, but also in smaller resistance excercises, including bench press and isolation excercises. Research indicates that the larger more involved excercises, like squats and deadlifts, will have the largest increase in Testosterone and Growth hormone. Although all resistance training has this effect, a curl for example, would have only a very small increase in Testosterone and Growth hormone. A study published in (Int J Sports Med. 1991 Apr;12(2):228-35) showed this hormonal increase after weight training in both men and women.
I was glad to see there is research to back up that squats and deadlifts are good for increasing testosterone levels. However, there is one major caveat. According to studies it seems to be temporary increase, as a few hours to about a day later, your Testosterone and Growth Hormone levels drop below normal and cortisol remains high. This is where your body is recovering hormonally and people warn about overtraining.
After about a couple days your testosterone levels will return to the same or maybe even slightly higher. I couldn’t find any research that showed those who squatted or weightlifted in general, have significantly higher body testosterone levels long term. In fact, you have to be careful of overtraining. In a study published in (Med Sci Sports Exerc. 1993 Aug;25(8):929-35), strength lifters who came back from a break of weight training, had a surge in testosterone and lowering of cortisol levels. Therefore, taking a break was actually a good thing for them for restoring / increasing their anabolic hormones. If anything, it looks to be long term weight training, is more likely to cause lower testosterone levels than higher levels, if you don’t take a break from training every few weeks and watch workout volume.
Do squats help increase overall muscle mass in body?
This is a little more difficult question to answer. There is no research directly on it, but if we use some logic here, we can probably answer the question. When you do squats, your releasing a substantial amount of anabolic hormones that your whole body can feel the effect. When your testosterone increases in your blod, it reaches all parts of the body. It’s not like your arms are going to grow significantly from just a leg workout, but I believe the testosterone increase in the blood can cause muscle growth to other parts of your body. Steroids help you grow by increasing testosterone in the blood, so it makes sense that squats could have a similar stimulus effect on other muscle parts in the body.