I would refer you the posting on this board regarding Body by Science, Dr. Doug McGuff.

http://paleohacks.com/questions/656/body-by-science-hype-hack-paleo

I have done one round of P90X at 66 years old and it did get me on the road to more strength and I am doing great.

Dr. McGuff advocates high intensity short duration training...taking the muscles to near failure...for 15 minutes a week and then rest 7 days for the body to regenerate itself after the teardown of the muscles. He has the science behind his work. You should buy his book and look at not beating your body up so much....and free up a lot of time.

I do his big five lifts and have increased my overall strength by 40%.

Yes, I believe if you continue on at the level of exertion you are now on you are headed to a less state of wellness later in life. I would put you into the same classification as chronic runners who beat themselves up and go to an early grave. See this posting: http://paleohacks.com/questions/2469/long-distance-running-and-heart-disease

You have a good foundation on which to continue and I applaude your determination and mental toughness to power through Insanity and P90x.

Now slow down. You will not lose anything by incorporating Dr. McGuff's training regime.

As an aside, Melissa on PaleoHacks also lives in NYC and was featured in a NYT article about Paleo eating cavedwellers.
http://www.nytimes.com/2010/01/10/fashion/10caveman.html They have a meat up once a month at: http://www.meetup.com/Eating-Paleo-in-NYC/ Her website is: http://huntgatherlove.com/

Wrong question.

How little exercise is enough?

;-)

Exercise tolerance is an individual matter. I have no idea if your level of exericise is unhealthy for you, but it may not be optimal depending on your goals. Your first step should be to define your goals. You seem to be saying that you're approaching your ideal weight. Maybe it's time to scale back into a "maintenance" program. What about body composition? Muscle mass? Functional/sports-specific goals? Design your exercise regiman around your goals.

Sisson and McGuff have what I would call minimalist exercise philosophies--what is the most efficient and effective use of your (limited) workout time? This leads to brief, intense, relatively infrequent workouts. If you don't truly enjoy working out, then spending more time than you have to is a waste.

If you walk everywhere, you're already doing enough cardio. Why are you doing additional cardio? The 75% heart rate zone is getting into "chronic cardio" according to Sisson, which is pro-inflammatory.

In summary, I agree with Sisson's philosophy and program. Cut your strength workouts to 20 to 30 minutes. Keep walking and sprinting, but cut out the extra cardio. Adjust your program according to your goals and results.

I don't think you have to worry about too much activity in itself. You can still maintain very high activity levels and maintain your health! There would be nothing unhealthy or unpaleo about, for example, about hiking with a load for very extended periods or something physically analogous. The problems would come from too much activity at high intensity levels.

High intensity stuff is the backbone of your fitness regime, either weight-lifting of the BBS or traditional strength-training way or sprints, the point not being to burn calories or 'be active' but to stress the body in a very short period and force lots of adaptation and improvement. It'll take at least 2 days to a week to recover if done properly.

In between the intense activity I think you can have as much light activity as you like, the point being just to deplete muscle glycogen or fat stores rather than force any substantial adaptations, by stressing the body or breaking down muscle. The point is not to 'repeat the stimulus' of your intense workout while your body is still recovering from it, better to let your body recover from the ultra-intense workout and then have an equally intense one.

Too much too intense activity in between is only going to breakdown your body faster than it can recover and raise cortisol, as well as subjecting joints to more wear and tear with no benefits. Obviously it's difficult to quantify how much intensity is too intense in these in between sessions, but both McGuff and Sisson's suggestions that it should be fun and appealing rather than torturous and stressful are good starting points. Then see how long it takes you to recover from workouts, how much you ache, whether you can perform on a paleo-LC diet or whether you find yourself needing to add empty carbs just to fuel extra activity etc. As McGuff notes, as you improve performance through the intense training, you feel the urge to naturally up activity levels anyway.

I think there's always going to be a practical compromise between what's healthiest and what's possible in a modern setting. Ideally you could get your moderate-intensity, glycogen/fat-burning activity over the course of a day every day. Trying to squeeze that into a 45 minute block per day is essentially impossible, since the right level of intensity would be that-which-you-can-maintain-for-most-of-a-day, so it's always going to be a compromise.

@Chris D

I suggest you re-frame around fitness and health. As Kurt Harris astutely points out: Fitness is not health.

Read these great posts.

http://www.paleonu.com/panu-weblog/2010/3/21/still-not-born-to-run.html

http://www.paleonu.com/panu-weblog/2009/11/1/cardio-causes-heart-disease.html

New to Paleo - Primal (Enjoying it!)

Quick question in regards to Crossfit training and Primal lifestyle.

Is crossfit Primal? Are the workouts pretty much High intensity most of the time?

I like the idea and enjoy high intensity workouts, now that I'm reading the Primal Blueprint and the 75% heart rate zone idea, I'm feeling a little confused... would anyone like to clarify? OR is there really no right or wrong :)

If you are afraid of losing your fitness level, try the following:

• test your fitness
• decrease workouts (e.g. frequency) for a certain period (e.g. a month)
• retest your fitness

if the retest is as good as the first test, you were doing fine during that month.

or maybe you're still working too much? do the same thing again until you find the 'minimal amount of work' you need to do to keep your good fitness.

Often you will find that a decrease in work does not mean a decrease in fitness level, but on the contrary, you could improve!

Generally I find Mark Sissons approach to exercise very wise. The heart rate under 75% doesn't feel like exercise? Well, maybe that's the point!

Good luck.