Should you perform High Intensity Training or Low Intensity Training, or a combination?
There are merits to both styles of training but lets first define the two terms.
I have chosen not to discuss moderate intensity training, not because it doesn’t have value, as it certainly does, but more so because it is not a hot topic nor is does it have such extreme advantages, nor disadvantages, as the extremes.
High Intensity training is the meat and potatoes of athletes and elite fitness enthusiast around the world, or so it seems from the outside looking in. Which is why it has become such a fad among personal trainers, boot camp trainers and recreational fitness enthusiasts.
High intensity training drives neural adaptions which is a primary driving force for increasing strength, power and speed. No doubt, the best athletes in the world have spend quite a bit of time training at high intensities. As a former competitive Olympic weight lifter and strength and conditioning coach, I am certainly a proponent as I have seen its value first hand. On the aerobic side it increases VO2 max, stroke volume and hr max, all resulting in increases in performance. It also, elicits large releases of anabolic hormones (testosterone, growth hormone).
And it requires less time to get better adaptations than low or moderate intensity work.
But the down side of high intensity training is that it is hard on the central nervous system, promotes muscular strength and power but not connective tissue adaptation, demands the endocrine system to go into overdrive, and is harder on joints. So if this is your primary form of training, the short term effects are nervous system fatigue (noted by deterioration of strength, power, speed, and coordination, with chronic effects showing a variety of effects including muscle twitches). Whereas the long term effects are chronic tendinitis and muscle ruptures, arthritis, and even endocrine failure (the chronic lowering of anabolic hormones, especially testosterone). Again, that doesn’t men that it bad, but it will catch up to you if you do too much.
Low intensity training on the other hand is typically viewed as the two old ladies walking down the street or the the soccer mom with the pink dumbbells in the corner. So we tend to look down upon it but it does have some upside. First, sure, you do have to do a lot of it to yield “results”.
But we should specify what results really are here. Any activity is good metabolically and there is only so much high and moderate intensity work that you can do and recover from. This is really where low intensity work comes in. Rather than being a driving force for adaptation it is a driving force for recovery and disease prevention associated with metabolic disorders. In this regard it is has a priceless value. There is almost always a way to get it in, and it will help prevent injury and the anabolic collapse associated with too much high and moderate intensity work.
Ultimately, all three training intensities have merit. The challenge is finding the time and a way to include all three training methods and balancing their volume and frequencies to best suite your body and your goals. If you are not including all three, you should be, and if you are but feel like your dancing a fine line then you likely need to make an adjustment. From a longevity standpoint, I would lean slightly on the side of more recovery work.