*UPDATE* Psychological Effects of Heart Rate Monitor Use Study

12/21/2010: Preliminary results were reported at Indoor Cycle Instructor in October 2010. Manuscript in preparation. Once published, results will be made available on this site and at ICI.

Wednesday, June 4, 2008

How to Become a Fat-Burning Machine

As many of you know, I continued my irresponsible jet-setting ways (for the woman supporting herself entirely by Spinning, that is) this weekend -- this time, down in Miami for the annual World Spinning & Sports Conference: a 4-day continuing ed conference attended by over 1,000 instructors from around the world. It was awesome!

I will be writing tons of posts over the next few weeks to share various training principles (nothing I haven't shared -- or attempted to share -- with you before... but perhaps more effective ways of communicating these principles in a way that better 'drives them home' for you?). For now, though, I want to share with you an experience I had for my own training that underscores the concept of aerobic base-building -- towards the end of becoming fat-burning machines!

As many of you know, we try to individualize our training according to heart-rate for purposes of making our metabolism work for us (instead of just fighting it... or even just complaining about it!). Exercise intensity relative to metabolism is truly what determines the effectiveness of all that time you spend in the gym. Scores of students tell me on a daily basis about how they've been training hard for years and years and "yet" are still not losing any weight, and they are tremendously frustrated. Very common, but very unsurprising.

Why do I say this? Because of how the body fuels itself. We tend to think "more" is always "better" - but it's actually not true. Below a certain heart rate, the body utilizes mostly fat as its main source of fuel. Above that certain heart rate, the body uses mostly sugar. By training above that point without having first established an "aerobic base," you are actually training the heart to prefer to burn sugar, not fat, at rest. So all those PsychoSpin instructors who have you doing crazy "sprints" (which are commonly not real Spinning sprints, usually -- but the word "sprint" tends to get people excited, so instructors toss the word around for mere accelerations) every day, this is not necessarily going to help you burn fat. At extreme high heart rates, you are mostly burning sugar (and if you run out of sugar, you'll start breaking down muscle), leaving you sore and feeling hungry (which then sets off a whole 'nother cycle...).

If, however, you can "re-boot" the heart by training it in that lower aerobic heart rate zone (below 80% MHR), you can actually re-set your metabolism. While you will burn fewer calories in a 45 min period, those calories will be coming from FAT instead of sugar.... and by re-setting that metabolic rate, your body will continue to work for you all day long. While you're laying on the couch watching TV or out sipping a glass of wine at an outdoor cafe... yup, you'll be burning fat the whole time. Love it.

How do we pull this off? First, get a heart rate monitor. Second, chat with me about how to use it (hint: your age-predicted target values are probably not entirely accurate, as they do not account for conditioning level). Third, commit to the following short-term sacrifice... towards the end of long-term fulfillment.

Behold, your invitation to burn some fat:

Discipline yourself to remain below 80% MHR (or, below your lactate threshold - if you know it) throughout all cardio exercise (not just Spinning). You will be improving your cardiovascular fitness, and you will see and feel this measurable improvement in a matter of weeks.

This may mean that you have to modify your usual efforts. In a Spinning class, if an instructor (including me) tells you to rise out of the saddle -- if you can't do that without crossing 80% MHR, don't do it. Whatever modifications you have to make to maintain that base-building plan, just make them. This is your body. Your training. You're calling the shots. Over time, however, you will start to notice that you're able to do more and more (closer to your former efforts) while still remaining below 80%. This is called adaptation, and it's very cool.

I've been talking about this for a looooooooong time (on the left-hand side of this blog, click the links for "endurance," "HR training," and "periodization" to start!), and many of my students have found great success with their base-building efforts in that they have started to lose weight, find themselves physically and mentally energized, sleeping better, and performing better in all of their recreational and competitive athletic activities.

But now I'm going to tell you how base-building worked for me:
In 2005, I started training with a HR monitor. I had been cycling religiously 3-4x per week for several years, and had not lost a pound. I was 40 lbs heavier than I am now. When I started training with a HR monitor and staying entirely below 80% MHR, I lost 20 lbs in two months (with no major dietary changes), and ultimately came to lose another 20 over another four months.

<<--- (Top & Bottom): 2003, even while Spinning 4x per week! Before training with a HR monitor and staying exclusively below 80%.

It was crazy -- and yet, not at all. It was just science. Above lactate threshold (for many people, this value occurs between 75-85% MHR), fat is not the predominant source of fuel. If we train above that point, we are mostly NOT touching our fat stores (Occasional anaerobic effort important to incorporate into any training plan, for other reasons --but it still does not burn fat!)

What I've been leading up to: this weekend, I had my aerobic base and metabolism actually measured to determine at what HR my body is still using fat as its dominant fuel. I rode a Spin bike while wearing a special piece of equipment that monitored my respiration and heart rate as I exerted myself at various degrees of intensity. For most people, they are burning the greatest PERCENTAGE of fat calories (below 80%, we burn fat and sugar) at very low heart rates (55-65%-ish). We very rarely train at those low rates when we're at the gym. But yet, it's training at these moderate intensities (for example, 70-80%) that ultimately helps us raise that aerobic base so that our greatest percentage of fat burning occurs at HIGHER heart rates... so we can burn more calories, get that endorphin "rush," and all that good stuff... but still be burning fat. Lance Armstrong, by the way, burns the greatest percentage of fat calories at his anaerobic threshold... he's essentially burning fat all the time. But Lance spends 12 weeks a year training at 60% of his MHR. All I'm asking YOU for 8 weeks of just below 80%!

Over time, the goal is to build up to being able to sustain the upper limit of that <80% range for entire training sessions.

Getting more work done, without working harder.


Courtney said...

Thought you would find this interesting, do you read?
What are your thoughts on what to eat before and after work outs, oh spin guru?

Melissa Marotta said...

Thanks, Courtney! I'm typically a pre-morning class Times reader, except for Thursdays when I read at night, so I hadn't seen that yet. Not surprising that their position is that there is no specific ratio between carbs/protein loading before/after exercise, and that energy bars/drinks are overrated. I agree. EAT REAL FOOD, a combination of carbs and protein.

Disclaimer: I am not a dietitian. I can share, however, how I manage my own dietary intake while training. My personal opinion is that 60-90 minutes before exercise, it's a good idea to eat something light but sustaining (that combines carbs, protein, and fat... the fat makes it last). My personal choice for pre-workout meals are either 1) egg whites and soy cheese on brown ricecakes, or 2)peanut butter on ricecakes. Nothin' wrong with regular cheese or whole grain toast - I'm just gluten- and lactose-intolerant, is all.

After exercise, I personally replenish carbs/protein within 20 minutes of exercise to keep my blood sugar steady (and find that, if I don't, I crave sweets... and a lot of them... which is a wee bit counterproductive). Before I leave my apartment, I pack a zip-lock bag with a handful of almonds. So right after Spin class, for example, I eat those with some fruit (very big into berries, for their antioxidant properties). Or if I know I'm coming straight home after a training session, I blend a quick smoothie out of frozen berries, fat-free milk (lactose-free, of course!), a packet of Splenda, and a spoonful of protein powder.

Either way (home vs. road), within two hours, I make sure to eat something more substantive - like some grilled chicken with salad/vegetables/whatever.

That's not to say that I never eat energy bars. I usually have one with me (as a personal rule of thumb, I don't replace meals... real food for real meals, always). But if my blood sugar starts to dip, a lower-calorie energy bar -- I personally refuse to eat a bar with more than 140 calories -- can be a good source of carbs/protein.
Bars aren't meals. They're snacks.

Take-home points:
1) Exercising hungry is bad.
2) Protein/carb/fat mixes are good, though a rigid ratio is not something I personally concern myself with
3) Peanut butter is amazingly valuable for exercise fuel, as are nuts... but I personally find both easier to enjoy OUT of my house, once the portion is pre-prescribed and packed ahead of time.
4) Eat real food whenever possible.
5) Watch out for the sugar in fruits. Bananas, for example, are fantastic in that they have a lot of potassium to help maintain your electrolyte balance whilst sweating a lot (when I did those two 6-hour Spinathons in the winter, bananas were key). But they have a very high glycemic index, often overlooked. My old boss (a doctor, no less!) used to eat 3 bananas before he went to the gym. No, dude.

margot said...

This is the best explaination I have ever read about HR training. Complete with motivational images! I'm working hard on this 80% and below.

Anonymous said...

Hi Melissa,
Just found your blog and I'm really enjoying it, thank you!

My Anaerobic Threshold is 178. Does this mean that for 8 weeks, I should not exceed 178 or 70% of 178?

Thank you! I am looking forward to being a fat burning machine!

Melissa Marotta said...

Thanks for writing - glad you're finding my rantings marginally useful. Must clarify! 70% LT is a great active recovery day. For your base-building efforts, all that matter is staying below LT (with occasional surges to actual LT). Staying between 80% and 102% of LT is great! You have great flexibility within that zone. Longer training sessions (60-90 mins), hold 80% LT. Shorter sessions, try sustaining 95% LT. You can incorporate aerobic intervals on top of these "steady state" trainings. Hope that helps!

Anonymous said...

Thank you so much, Melissa! This explains why I easily lose weight when jogging (11 min/mile pace) is my main activity but I haven't lost weight with all the spinning I've been doing (where I tend to be an anaerobic junkie). I've had a heart rate monitor for years but haven't used it much. Your blog inspired me to order a new chest strap (can't find mine) and get serious. Thank you!