Living in the Zone

Last time I  mentioned losing about 12 pounds, increasing my fitness, and that I am actually becoming able to ride non-trivial distances on rail-trails.  So, how’d I do it?

Aside from just plain work, that is?  Tools.

When writing commercial software, there comes a time where you need to optimize your code.  You need to figure out why it’s slow.  Long experience has taught me you can never trust your gut instinct, since it will be wrong. You have to take measurements.  You use tools to isolate the problem (and it’s always a surprise).  Then you fix it, and then measure again.

Likewise, I knew that getting reconditioned would require some tools.

You may have seen the the Heart Zones Training logo in the Cycling Room.  I’d seen the wall charts filled with numbers, having no idea what any of it meant.  Then I saw the Sally Edwards “Heart Zones Training For Cyclists” book lying around the Smoothie Bar and flipped through it.  I saw something interesting on every page.  So I went to Borders up in The Mills and got a copy for myself. As anyone who knows me can tell you, I’m an information sponge. I love learning new stuff.  Especially if it’s nerdy.

Global Ride offers a “Threshold Heart Rate Testing” workshop.  It condenses the book and makes the Heart Zones concepts very approachable.  It’s nice being able to ask questions and get immediate answers.

It requires a heart rate monitor.  But I like electronic toys, so this was a good excuse to get a new one.  You can borrow a heart rate strap and see the display on the Keiser bike’s display.  I have a Garmin unit that talks to a wristwatch.  I put the watch on the handlebars so I can keep track of my heart rate.

So, having devoured that book I knew what to expect from the workshop. It takes about 2 hours. You start with a half hour going over the basics of Heart Zones training, then an on-bike “threshold test”, which involves a warmup, then reciting some text, increasing your heart rate, reciting the text again, until you can’t recite it any more because you’re breathing too hard.  Sounds weird, but it works.  Afterwards, you take the numbers from that test and figure out what your Heart Zones are.

OK, so what *is* this heart zone stuff?  It all about how your muscles are  fueled.

huh?

Your muscles basically run on sugar.  There is a finite amount of sugar that’s actually stored inside of your muscles, going by the scary name of “muscle glycogen”.  You burn this fuel when you turn the cranks of the bike.   As you exert yourself, body fat gets converted into glycogen and replenishes what you burn.  You can conceivably continue indefinitely,  converting fat to glycogen and burning that in your muscles.

As you work your muscles harder, though, there comes a tipping point where you’re burning the muscle glycogen faster than you can replace it.  Once you run out of that stuff, you “bonk”, and just can’t go forward.

Also, our bodies are not 100% efficient systems.  Biological processes generate waste products.  In this case, “lactic acid” (another scary name).  Your bloodstream carries away this waste.

Ok, enough with the anatomy 101.  What’s this heart zone stuff?  With the threshold test you took earlier, you can calculate a series of ranges of heart rate.  These ranges, also known as zones, are numbered, and have definite behavior:

Zone 1 is an easy, low-intensity zone, handy for warming up.  Working out in this zone helps reduce stress, improve your blood pressure, and gives your hair that healthy glow.  You’re burning your muscle glycogen, and it’s getting replaced by converting fat.

Zone 2 is more intense, but still fundamentally easy.  This is a good recovery zone if you hammered yourself recently.  Similarly, you’re burning your muscle glycogen and it’s getting replaced by converting fat.

Zone 3 is where you start getting aerobic improvement.  You’re still burning fat, but you’re training your body to burn more of it.  It also helps your circulatory system, causing it to grow more capillaries and improve the efficiency of what you have.  You could work out for months in just Zone 3 and see vast improvements in overall health.

Zone 4 is where it starts to get interesting. You’re working harder.  This is where you start to build cardiovascular strength.  You’re burning fat, but you’re also burning more muscle glycogen than you can replenish, but you can still sustain this Zone for an hour or two. You’re generating lactic acid, “feeling the burn”, but it gets cleaned out pretty efficiently.  You’re burning a lot of calories here.

Before we get to Zone 5,  let’s talk about waste a bit.  Those of you with kids at home (or live with a kid-at-heart) know that sometimes mess can be generated faster than you can clean it up.  Likewise, as you work your muscles harder, these biological waste products build up and can’t be cleared fast enough.

Zone 5 is on the other side of your “threshold”.  This threshold is the point where your circulation cannot clear out the metabolic slag from your muscles fast enough, so it builds up.  As the waste builds up, your heart beats faster to try to clear it out. You can’t sustain Zone 5.  Eventually you’ll either fill up with lactic acid, or your cardiovascular system will cry Uncle and force you to take some recovery time.  That said, time in Zone 5 can really improve your cardiovascular fitness.

If you’re really deconditioned, you’ll want to spend a lot of time in Zone 1 and Zone 2. Build up a good fitness base. As you get in better shape, you’ll want to spend more time in Zone 3 to improve your aerobic capacity and teach your body to burn fat faster.  Spend time in Zone 4 to get stronger, and teach your body to clear out the lactic acid more efficiently.  Spend time in Zone 5 for maximal strength, and to build endurance.  And, frankly, to teach your psyche to endure exertion.  I won’t mention the term “suffering” (oops, I said it) but you know what I mean.

This is how I use the heart zones.  If I’m in a recovery mode, I stay in Zone 2 or 3, even if everyone around me is working really really hard.  But I’m also working on my overall strength so I can climb hills, so I spend more time in Zone 4 and occasionally Zone 5 to improve both leg strength and cardio capacity.

In addition to using  zones to direct your training, you can also use these zones to make sure that you’re being honest during your workouts.  If Lorraine says during a class “you should be working pretty hard now”, and you’re in Zone 1, then you’re probably just slacking off.  You should push yourself to Zone 3 or 4, either by increasing your gear, or cadence, or both, or doing some standing.  Likewise, if she says “this is a recovery song”, and you’re still up in Zone 4, then you need to ease off on the gear or cadence until you get down to mid Zone 3 or high Zone 2.

You can also use the zones to judge your improvement over time.  You may be in Zone 4 while pushing Gear 10 at 90 rpm, and then the next month, you’re in Zone 3 pushing Gear 10 at 90 rpm.  Congratulations! You’re now fitter, and can generate power more efficiently.

Power?  Did I say Power?  Yes!  That’s what I’ll talk about next time.  Stay tuned.