The short- and long-term benefits of exercise are absurdly well-documented. Exercise lowers your cholesterol, boosts your mood, decreases your stress, and increases your flexibility (plus about a zillion other good things).

In an increasingly packed daily schedule, though, carving out the time to fit in a workout can be a challenge.

Enter new research that shows you can get away with as little as one minute of effort.

Here's the deal: Scientists out of McMaster University conducted research on interval training, which is short bursts of high-intensity exercise followed by periods of either rest or lower-intensity work. Put more bluntly: sprints.

To see just how little you can get away with when it comes to interval training for health purposes, the researchers brought in 25 less-than-in-shape young men (future studies will focus on women). They tested their levels of aerobic fitness and their ability to use insulin in the right way to control blood sugar, and biopsied their muscles to see how well they functioned on a cellular level.

Then they split them into a control group, a moderate-intensity-exercise group, and a sprint interval training (SIT) group.

The control group did nothing differently at all.

The moderate-intensity group did a typical I'm-at-the-gym routine of a two-minute warm-up, 45 minutes on the stationary bike, and a three-minute cool down, three times a week.

The SIT group did the shortest interval training ever recorded thus far by science. Participants warmed up for two minutes on a stationary bike, then sprinted full-out for 20 seconds, then rode for two minutes very slowly. They repeated this twice (for a total of three sets). The whole workout took 10 minutes, with only one minute being high-intensity.

All of the groups kept at it for 12 weeks, or about twice as long as most previous studies.

The results?

The control group, as expected, had no change in results.

The two other groups enjoyed results that were basically identical to each other's. In both, scientists found a 20 percent increase in cardiovascular endurance, good improvements in insulin resistance, and significant increases in the cells responsible for energy production and oxygen in the muscles (thanks, biopsies).

That is remarkable. By the end, the moderate-intensity group had ridden for 27 hours, while the SIT group had ridden for 6 total hours, just 36 minutes of which was arduous.

This means one group spent about 10 total minutes on each workout, while the other spent 50 minutes. The SIT group got the same benefits in a fifth of the time.

As Martin Gibala, the professor of kinesiology who oversaw the study, said, "If you are an elite athlete, then obviously incorporating both endurance and interval training into an overall program maximizes performance. But if you are someone, like me, who just wants to boost health and fitness and you don't have 45 minutes or an hour to work out, our data show that you can get big benefits from even a single minute of intense exercise."

The fact is, a lot of us spend more time at the gym because we think it's better for us. We jog while watching TV; we do the stationary bike while reading a magazine; we lift weights at a moderate level for 30-60 minutes.

But the hard scientific fact is that we could get the same results from one minute of flat-out exercise.

Convinced? Here are three sample interval workouts. None requires a gym:

1. Wind sprints

If you live near a hill (it doesn't have to be terribly steep; any incline works), walk or jog to it to warm up. Sprint up it for 20 seconds. Rest while you walk back down. Repeat at least three times (for a challenge, work up to six-plus sprints). At three sets, this will take you a total of only five to seven minutes.

2. Stairs

This is great if you travel for work a lot and stay in hotels. Run as quickly as you can up a few flights of stairs for 20 seconds (bonus points for skipping stairs). Again, start with three sets, but aim for six-plus. It'll take about seven minutes. (Note: avoid running back down the stairs; it's not great for your knees. Take the elevator down if necessary.)

3. Jump rope

Another good one for a simple, easy, portable workout: Do a short warmup, and then jump as fast as you possibly can for 20 seconds. Jump at an easy to moderate level for two minutes. Repeat three times.

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