If you are a Lean, Solid Dog, you need a lot of rest.
By a quirk of history, Americans took much of what we “know” about fitness from a terrible source, bodybuilders. Why terrible? Because since the Seventies, bodybuilding has been transformed a few times over by steroids, and if you are training with “Vitamin S,” then you are operating with a whole different physiology than the rest of us. Therefore you don’t have much training advice that can apply to people not using mind-blowing “Russian supplements.” * Think of drug-assisted athletes (and they are now the norm) as almost a different species from yourself, and taking your ideas about training from them is like following the nutrition plan of a zebra.
It is from bodybuilding that Americans got most of our counterproductive “no pain, no gain” illusions about fitness. If you were juicing, you could get some use from that approach, just like the Incredible Hulk can perform great even without a rubdown and a nap. But you, dear friend, unless you are a professional hardman hardperson, you probably don’t need more than one challenging strength and aerobic session every week or so. What you do need a lot of is “active recovery.”
It’s a cliché of training that “You don’t get fitter from exercise, you get fitter by recovering from exercise.” And it’s a cliché because it’s true. Your muscles don’t grow while lifting weights, for example. They grow afterward by taking in nutrition and thickening in case they get worked hard again.
That is how steroids work too. They are not exactly performance-enhancing drugs, they are recovery-enhancing drugs. They make you bounce back from training faster and higher, and that’s how they improve your performance indirectly.
For a lazy person like me, it’s wonderful to know that I can limit serious exertion to one or two weekly bouts and then use the rest of my “training” time on rest and recovery. Yes, it’s true that we really should get exercise every day. But what we’re looking for is “active recovery.”
You rest better and quicker through active recovery than passive recovery, i.e. sitting on the couch. You just do light activity that makes you breathe a little harder and get some blood and endorphins flowing, but that’s all! As a rule of thumb, you are doing it right if you are breathing a little more deeply but you could hold a conversation or sing a song without feeling short of breath. This could be just walking or riding your bike for transportation. Similarly for light (!) hiking.
For fairly serious athletes in any discipline, I think the king of active recovery is yoga. You go for the active recovery and in the bargain you also get invaluable prehab and rehab, which no one gets enough of, in an environment that is also a huge serotonin factory AND full of lithe, beaming people.
* Note: I don’t necessarily poo-poo drug-assisted training as morally inferior or easier. On the first point, I exercise because it makes me so happy, not so I can imagine myself as someone else’s better (as if anyone cares anyway). Second, drugs don’t exactly make training easier. If you think that, start squatting under a bar that’s 200# heavier than you use now—do it however you have to, I don’t care—and then get in touch to tell me about how easy your training has become.