How Much Exercise Do You Really Need?

If you don’t read the actual study and only listen to the sound bite headlines in the media, you’d walk away thinking that women need at least an hour a day of exercise to keep weight off. Understandably, that’s discouraging for a lot of people, especially those with busy lives. It’s also about twice the current federal guidelines of 150 minutes a week (or 30 minutes, five days a week). And it’s partly true — until you look at the details.


Let’s start with the federal guidelines (30 minutes of moderate-to-intense exercise, five days a week). These guidelines were meant to prevent disease, and a ton of research has shown that walking at a moderate clip five days a week for a half hour at a time will do just that. That kind of exercise will indeed lower your risk for dying, improve your heart health and actually — according to research at the University of Michigan — even grow new brain cells!

But, as I’ve said many times, it won’t make your body bikini ready, and for many people it won’t result in weight loss at all. To prevent more weight gain, you need a lot more. A 2002 report by the Institute of Medicine suggested 60 minutes seven days a week for that purpose, closer to the present study’s findings. But — and this is a really big but — there’s one important detail that everyone reporting on this study seems to have forgotten: Diet.

In the current study, diet wasn’t monitored at all. The researchers reported on the amount of exercise it took to keep weight off for women “eating a normal diet.” A normal diet? In America? You’re kidding, right? Nope.

As trainers like to say, “you can’t out train a bad diet.” So, if you don’t tackle the eating issue, it’s gonna be really hard to lose (or even maintain) weight with exercise alone.

In defense of the researchers, they didn’t just accidentally “forget” to control for diet. They wanted to see how much impact physical activity alone would have on weight assuming people didn’t change the way they eat. And the answer was: not all that much.

Truth be told, exercising alone — without dietary changes –did help a bit, particularly for women who weren’t very overweight to begin with. For those not-too-overweight women, about 60 minutes a day kept weight gain to a minimum over the course of the fifteen-year study. But 60 minutes had less of an impact on people who were significantly overweight to begin with, which makes sense, since without dietary changes we can assume these women were eating a lot to begin with and were continuing to do so throughout the length of the study.

The bottom line is that while exercise matters — and it most certainly does — it’s just not enough to get the job done if you don’t make some serious changes to the way you eat. Unless of course, you are Michael Phelps. Then I guess you can eat whatever you want, as long as you spend eight to 10 hours a day training.


Shortcuts to Faster Running


There’s something so appealing about the 15-minute workouts and the promise of making fitness gains in little time, especially in these slushy, snowy days of winter that can make running seem like a chore. What’s the get-fit-quick equivalent for runners? Rockie James, owner and head coach of The Fitness Center in New York City has the answers — hill and speed workouts that can be done outside or on a treadmill. Whether you’re forced to cut workouts short due to fewer daylight hours or frigid temps or just generally short on time, promises that you’ll see gains just by adding one of her workouts to your weekly running routine.

Hill Workouts

This can be done on a treadmill or outside. Warm up with 10 minutes of easy running, then stretch for a couple of minutes. Next, you’ll run uphill for one minute. If you’re on a treadmill, use a 4 to 6 percent incline. If you’re outside find a hill that isn’t “so steep that you feel like your mouth is kissing the ground, but steep enough that it still feels like work,” said James. Rest at the top of the hill, then run back down the hill. If you’re on a treadmill, lower the incline and walk for 30 seconds. Rest for two minutes and repeat three more times, then cool down with 10 minutes of easy running.

If you’re a more experienced runner, James suggests trying to run faster with each of the uphill intervals. “Just be sure your first run isn’t really fast or you’ll be too taxed at the end,” she cautions. Another advanced option: Instead of going faster, you could further, she said. For example, if running one minute uphill doesn’t bring you to the very top, aim to get a little closer to the top on each of your subsequent runs.

The benefit of the hill workout? “For one, you’re getting it done faster. Also, a lot of runners often only run one pace or only on mostly flat surfaces. Giving yourself the opportunity to do hills is important if you want to travel to a race, let’s say the New York City Marathon, which has lots of hills. You have to know your body can handle that,” she said. “It also makes you a more effective and efficient runner,” James said. “If you did this workout once a week for four weeks, when you’re on flat ground you’ll be able to go faster with less effort.”

Speed Workouts

These can also be done on a treadmill or outside. Again, you’ll warm up with 10 minutes of easy running. Then, run fast for 30 seconds, slow for 60 seconds and repeat for six to 10 minutes with no resting in between. What qualifies at fast and slow will vary by person. James advises thinking of your fast pace as your 5K race pace and your slow pace as your average training pace. More experienced runners can do a second 6-minute set with 1 to 2 minutes of rest or slow running in between. Then cool down with 10 minutes of easy running.

How do speed workouts help you? By recruiting fast twitch muscle fiber, which is what you’ll need to generate short bursts of speed and strength, as opposed to slow twitch muscle fibers, which is what you predominantly use for long distances, said James. “Your body needs to know how to recruit those fast twitch muscles when you need them for a race. It needs the muscle memory to be able to do that.”

These workouts may be time savers but they shouldn’t replace all of your regular runs. Instead, include one of these workouts in your routine each week. If you’re less experienced, do one every other week, she advises. “Even with every other week, after eight weeks, you’ll see gains.”