29 Jul 2010 workout

Today's workout was a zone 2 aerobic workout on the spinner.

Warmup: 3 min slow spin (HR < 110)

Workout: 42 min 18 sec in Zone 2 with 30 seconds of creep into zone 3

Cooldown: 5 min slow spin

HR @ end of workout: 138

HR @ t+1 min: 126 (-12)

HR @ t+3 min: 115 (-23)

Estimated Total Calories: 443

Changed it up a little bit after a revelation. During aerobic exercise skeletal muscle, heart muscle, and most all other body cells are generating energy through the Krebs cycle. When the demand for ATP in skeletal muscle (especially) is relatively constant and moderate, that energy production is fed through both β-oxidation of triglycerides and the pyruvate acid sequence (a.k.a. glycolysis). Whenever the body can feed that cycle through β-oxidation rather than glycolysis, it does so. At low levels of exertion, more fat is catabolized for the Krebs cycle and electron transport chain than are carbohydrates; the harder the exertion, the higher the percentage of carbohydrates, until you reach anaerobic activity which will stop all energy production through the Krebs cycle and switch to either only glycolysis or to the creatine phosphate system depending on how quickly the muscle needs to recycle ADP into ATP.

Short version: slow but still zone 2 workouts will burn more fat than a zone 3 or 4 workout will, and of course a 5c workout will be only anaerobic.

There's a school of thought that says "yes, this is true, but if you put out more effort you will burn more overall calories," a school that I don't disagree with because they're right. Except, what I'm trying to do is catabolize fat in order to lose weight, while also improving my cardiovascular fitness and capacities.

So, I switched today's (and every Thursday workout for the next few weeks) to a 45 minute spin on the bike & indoor trainer gadget at low-to-moderate zone 2 HRs, with the theory being that with a longer zone 2 workout I will be able to catabolize more fat and get smaller sooner. I will not be neglecting the capacity workouts, however, which are still scheduled for Sundays and Tuesdays.

In any event, the goal is still the same: lose weight, lose inches in my waist, neck, and other place where there's too much fat, and add CV fitness.

Sleep: 7/10 (Fitful sleep, as always when I'm on shift, but did get a good solid 5 hours before wakeup)

Fatigue: 2/10 (slightly fatigued, mostly from the shift I believe)

Stress: 3/10 (work stress elevated due to an in-shift incident, as well as LifeNet 12 going down in the city yesterday)

Soreness: 1/10 (slight R hamstring soreness)

Resting HR (@wakeup): Unable to test @ work.