March 10, 2011

He S.A.I.D, She S.A.I.D: Why Spinning Won't Make You Slim

Lately, I’ve been receiving quite a large amount of mail from readers bringing my attention to all kinds of great facts and foibles in the world of nutrition and exercise. Unfortunately, I can’t blog about each topic suggested, although many are certainly deserving of some attention, however, a recent query piqued my interest.

The question dealt with the usefulness of spinning (spin classes) as a tool for weight loss. Since I get this question fairly often, I figured I might as well answer it on the blog. Basically my view is as follows: if you want to use regular cardio as part of your weight loss program, ditch the spin bike and go run.

Fun? Yes. Good for weight loss? No.

Now since hearing this tends to upset people, I probably need to explain why.

Who S.A.I.D. That?

The human body is pretty cool… if not incredibly lazy. Although our bodies can and will adapt to pretty much any stimulus we throw at them (** adaptation can be a bad thing: we adapt to no exercise and crappy foods by storing more fat), we don’t really adapt to exercise stimuli unless we are forced to.

In other words, if you can lift something 15+ times without fatiguing or can carry out a conversation while doing your “cardio”, you aren’t placing any undo stress on your system… so no body composition remodeling ever needs to take place.

Clearly, it’s not even a question that intensity of the effort is a key variable when it comes to assessing the usefulness of an exercise to help us improve our bodies. But intensity isn’t the sole consideration. We also must account for the S.A.I.D. principle when it comes to figuring out an exercise’s usefulness.

Never heard of S.A.I.D. before? That’s ok… S.A.I.D. stands for:

  • S: Specific
  • A: Adaptations
  • I: (to) Imposed
  • D: Demands

In real world terms, this means that your muscles will grow bigger and stronger when you attempt to lift something heavy. Conversely, we’d expect your muscle endurance and cardiovascular system to improve when you subject your body to repetitive muscle contractions lasting many minutes (i.e. cardio).

The specific term in this principle also accounts for why we don’t get better at swimming just because we can run for 2 hours. The muscles needed to swim are wildly different than those needed to run. So while our cardiovascular system can improve with both forms of training, the skeletal muscles used have little to no carryover between disciplines.

Unfortunately, people assume that just because repetitive contractions expend a reasonably large number of calories, that all cardio training should then lead to weight loss… but that’s not always the case.

Here’s why.

Small, Strong or Skilled

In general, there are three ways to make movement easier: gain more muscle, carry less weight (generally in the form of body fat, but occasionally also in the form of less muscle as in the case of long-distance athletes) or become more efficient with our movement patterns (become more skilled).

Let’s call this the “small, strong or skilled” response to training. In other words, whenever you subject your body to a novel exercise stimulus, your body has to decide what’s the fastest route to improvement.

N.B. Remember that if you can already comfortably do an exercise, then no adaptation will occur. I can’t stress this point enough.

For most of us, improving our movement pattern happens first. Think back to someone learning how to skate. While you are learning to skate, your movement patterns are incredibly inefficient. Not only that, but you are tensing muscles all over your body to protect against falling… this act of activating the wrong muscles is extremely energy costly.

Man wasn’t meant to fly…

During the initial several weeks, skating expends quite a large number of calories. However, once you master the correct sequence of muscle firing, you become incredibly efficient and are able to skate for hours, as you learn how to conserve energy during the glide phase of each stride.

Unfortunately, as you become a better skater, you are no longer doing much for body recomposition.

The Sins of the Spin

Spinning follows a very similar pattern of “improvement”. Initially, spinning presents a challenge so you expend a reasonable number of calories while doing it. However, you rapidly become better at biking and learn how to effectively move your legs in a fashion that conserves the most energy possible.

While conserving energy is awesome if you are a competitive cyclist trying to win a race… this is an absolutely garbage phenomenon for individuals using exercise as a weight loss tool.

Compounding the negative aspects of spinning are the following factors:

  • no wind resistance to overcome
  • no side-to-side sway, little upper body activation
  • it is weight supported!

The first two factors are simple difference between spin bikes and cycling outdoors, but the last factor is the doozy.

Whenever you remove having to support your body weight from the cardio equation (i.e. spinning, elliptical, arc trainer), then suddenly cardio becomes a whole lot more ineffective for weight loss.

Remember back to the “small, strong or skill” outcomes I introduced earlier. In general, we expect cardio to produce a mix of skill/small. However, once we remove “having to haul my fat ass” from the equation, suddenly where’s the stimulus for becoming smaller?

This gentleman has likely done a spin class or two in his day.

At a resistance level of “10”, a big fat guy is always going to have an easier time pedaling than would a small, skinny chick. In fact, when you support your weight with a bike frame, movement typically becomes more efficient by:

  • your legs storing more fuel
  • your legs building more muscle tissue

Now I don’t know about you, but neither of these outcomes sounds like they are going to make people any thinner. Actually, the far more likely outcome from spinning is that it will make your legs bigger and more muscular, since that’s the quickest route to improvement for repeat sprint/coast biking activities that last under an hour.

Obviously, if you were to start spinning for 3-5 hours a day, then you might actually see some mass losses (take a look at a Tour de France cyclist vs. the picture of an Olympic cyclist above), however, most of us don’t have that kind of time to dedicate to training.

So when time to exercise is <5 hours per week and you want to use cardio as a weight loss tool, opt for running or the step mill. Since both of these activities require you to carry your entire body mass with each step (unlike the bike or elliptical), the logical adaptation your body will undergo is: drop mass.

Still not convinced that you need to give up the bike or elliptical? Then maybe some objective data is needed to change your mind… These calorie expenditure numbers are based on a man weighing 180 lbs.

  • Stationary Cycling (moderate intensity): 572 kcal/hour
  • Running 8 mph: 950 kcal/hour

Even for those mathematically challenged, it’s apparent that running at a moderate clip burns nearly 2x as many calories as does spinning!

So there you have it, there’s really no other way to “spin” the reality… spin classes are among the worst fat loss tools around.

Till next time, train hard and eat clean!

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Update August 21st 2012: To address many of the comments and questions that have emerged since this article was published, part II is live: A Fresh Spin on Cycling, Running and the Weight Loss Debate.

Update Sept 11th 2012: Dr. Johnny Bowden expands on the overall ineffectiveness of cardio exercise for weight loss in his piece “Exercise: The News You Don’t Want to Hear

graeme

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