Lactate

 For my workouts I use the ALACTIC protocol, which for weightlifting is 3 reps followed by a 30 second rest, and then 3 more reps until I get to the target which is usually 30+ reps.

So here's the deal with lactic acid. It stresses your body. Raypeat even suggests that avoiding it altogether would extend vigor and life. He recommends not even eating lactate,

 which occurs in fermented foods such as sauerkraut and yogurt. I was looking for ways to reduce the stress of working out because of my age, and because I noticed that hard workouts tended to trigger fibro episodes the next day. I'm interested in ways to get a decent workout without running myself into the ground, and ALACTIC seems to be one such technique.

Now, I don't go as far as Raypeat. The problem with lactic acid or lactate is inside the cell, and I would assume that if it were harmful, there would be some protection against it going from the stomach inside the cell. My best guess is that the amount of lactate in food is small enough, that, distributed over the whole body, it is nothing. In any case, sauerkraut is dang delicious way to get your cruciferous veggies and I'm not prepared to give it up.

Similarly, the real problem of lactate is when that becomes a constantly used metabolic pathway. If used for a short workout, the body can clear the damage and you are fine. In fact, it is certainly hormetic, if not overdone, and triggers a cascade of beneficial changes.

So lactate is a stressor, and a certain amount of stress is good. My background as a cross country runner makes me think that it is best used as a peaking tool. The typical running season is to slowly build up your weekly mileage, done at a relaxed pace. Then at 6-10 weeks before the most important race, you start doing speedwork, a.k.a. going at a sufficently hard pace to generate a lot of lactate. You don't want to do this faster running more than that because the risk of injury and burnout starts to increase substantially.

So too in the Gym. HIIT is a very lactate intense method. It gives good results. I expect that you need to build in rests, and times when you build a good foundation, or you will be prone to injuries and overtraining.