Is a 7-minute workout just as good as an hour-long bike ride? Yes, it can be.

Let’s face it, most of us don’t really like working out. Yes, there are those who are exercise fanatics, who go on and on about the “endorphin high” they get from a long run or bike ride, but these people are exceptions.

And yet it’s indisputable that regular exercise carries a host of health benefits, not only to your heart and cardiovascular system, but also to strength, mood, and overall energy levels. Exercise is just really good for you.

If you’re lucky enough to enjoy a sport that you can play regularly, you might get all the exercise you need without working out. But most members of modern societies simply don’t. Most humans seem to prefer a sedentary lifestyle.

To make up for sitting around most of the time, many people try to work out regularly. The question is, how long do you need to work out get those cardiovascular benefits?

Not very long, it turns out. That’s good news for those who don’t have time for hour-long workouts.

18 minutes is just as good as one hour. Let’s go back to 2005, when a study out of Canada, led by Martin Gibala at McMaster University, showed that very short, intense exercise–pedalling as fast as possible on on a stationary bicycle–was remarkably beneficial, even better than an hour-long bike ride. In just two weeks, the subjects of this study, who were all young and healthy, “increased muscle oxidative potential and doubled endurance capacity.”

You’re probably thinking, what do I need to do?

Well, for this routine, you need three 18-minute sessions per week. In each session, you do the following:

1. Exercise as hard as possible for just 30 seconds. On a stationary bike, this means you’ll pedal as fast as you can.
2. Followed this by a 4-minute rest period where you keep pedaling at a relaxed pace.
3. Repeat this 4 times, which will take a total of 18 minutes.

Voila! You are done. If you don’t have a stationary bike, but you can use another indoor exercise machine with equal effect (treadmill, elliptical, rowing, etc.) as long as it provides an aerobic workout.

You might have noticed that this is really just a 2-minute workout, in four separate 30-second bursts. But the 4-minute rest periods are important, so you need to plan for 18 minutes, and repeat this 3 times a week.

7 minutes is just as good as 45 minutes. Can we get benefits from an even shorter workout? Yes! A 2016 study by the same lab (Martin Gibala and his students) looked at the benefits of exercising all-out for just 20 seconds, with a short rest period in between, They found that a 7-minute sessions of “sprint interval training” (SIT) was just as beneficial as a 45-minute workout.

Again, you may be asking, what do I need to do for this routine?

For this routine, you use an exercise bike and do this:

1. Pedal furiously (all-out) for 20 seconds.
2. Follow this by 2 minutes of pedaling at a normal rate.
3. Repeat this 3 times, for a total of 7 minutes of exercise.

Repeat the whole routine 3 times a week.

(In the scientific study, the all-out phase used a machine that measured power at 500W, and the slower pace was at 50W. Some indoor exercise machines let you measure your output, but you’re not doing a science experiment here. Just pedal as fast as possible for 20 seconds, and you’ll reap most of the benefits.)

One small caveat here is that the routine used by the scientists added a 2-minute warmup and a 3-minute cool-down at a normal pace. So if you want to follow their protocol more precisely, you’ll need 12 minutes. Still, at 12 minutes this is much shorter than the 18-minute routine above.

How about 4-seconds? Okay, now we’re getting a bit ridiculous, right? But an even more recent study, just last year, looked at the benefits of 4-second high-intensity training, with just a 15-second rest period.

Of course, it wasn’t just 4 seconds of exercise. The subjects of this very small study (11 people, averaging 21 years old) at the University of Texas did 30 repetitions of 4 seconds each. More specifically, they “were asked to cycle as hard and as fast as possible for 4 seconds” on a specially equipped exercise bike. After a 30-second recovery, they did it again.

Repeating this 30 times takes about 17 minutes, but over the course of 8 weeks, the experimenters reduced the rest period to just 15 seconds, which reduced the overall session to less than 10 minutes. However, that’s not likely to work for most people, unless you’re a very fit 21-year-old. So I’m going to call this a 17-minute workout.

Repeating this routine 3 times per week produced benefits in both strength and aerobic capacity, much like the SIT training sessions in the Canadian studies.

So how do you do this “4-second workout” (which really takes 17 minutes)? Here it is:

1. Pedal furiously for 4 seconds.
2. Rest for 30 seconds, pedaling at a relaxed rate.
3. Repeat 30 times.

All three of these workouts I’ve described here can produce cardiovascular benefits equal to a 45-minute bike ride, and they only take 18 minutes, 12 minutes (7 minutes plus warmup and cool down), and 17 minutes.

The only downside of all these high-intensity workouts is that you might sweat, which means you’ll need to shower off afterwards. Another option (not backed up by such precise scientific studies) is a less-vigorous but even shorter 6-minute workout, like this one in the New York Times, which needs no equipment at all and should provide health benefits without working up a sweat. You can even do that one at the office.

So if you don’t have an hour to spare 3 times per week, how about 12 minutes? It can’t hurt to try.

What's the proper amount of dog for optimal health?

Humans have had dogs as companions for thousands of years. Over that time, dogs have evolved to become ever-better companions, as we humans selectively bred them for traits that we like, such as friendliness and loyalty.

Dog owners already know that owning a dog reduces stress. But it turns out that the health benefits of owning a dog go quite a bit further: two new studies published this month in the journal Circulation both found that owning a dog reduces your risk of dying.

The first study, by Carolyn Kramer and colleagues at the University of Toronto, reviewed ten other studies dating back more than 50 years, covering 3.8 million people. They compared dog owners to non-owners and found that dog owners had a 24% lower risk of dying, from any cause, over a 10-year period. The benefit was even greater for people who'd suffered a heart attack: those who had a dog at home after their heart attack had a 65% lower risk of dying.

The second study, by Tove Fall and colleagues at Uppsala University, focused on the benefits of owning a dog for people who have had a heart attack or a stroke. They used the Swedish National Patient Register to identify 335,000 patients who'd suffered one of these events between 2000 and 2012, about 5% of whom were dog owners. They found even greater benefits than the first study: among people who'd had a heart attack, their risk of dying was 33% lower if they owned a dog as compared to people who lived alone. The benefits were smaller but still significant for people who lived with a companion (a spouse or a child): they still had a 15% lower risk of dying if they also owned a dog. For those who'd had a stroke, the risk of dying for dog owners was 27% lower than for people who lived along, and 12% lower than for people who lived with a companion but didn't have a dog. This study measured the risk over a 4-5 year followup period.

These studies are consistent with many other scientific reports, stretching back decades. They're all consistent, and they all point in the same direction: dog ownership is good for your health. In fact, back in 2013 the American Heart Association issued an official statement on "Pet Ownership and Cardiovascular Risk" with this recommendation:

"Pet ownership, particularly dog ownership, may be reasonable for reduction in cardiovascular disease risk."

However, because the evidence was not very strong, the AHA also advised that people shouldn't get a pet "for the primary purpose of reducing CVD risk." In other words, don't get a dog if you don't want one. As every dog owner knows, owning a dog is much more trouble than simply taking a daily pill.

The new studies strengthen the existing evidence for the health benefits of owning a dog. In an accompanying editorial in Circulation, Dhruv Kazi from Harvard Medical School asks a critical question: is the association between dog ownership and reduced mortality just a correlation, or is it causal? He points out that studies have shown that dog ownership reduces blood pressure and other signs of stress, and that dog owners tend to get outside and walk more (with their dogs). Thus it's very plausible, medically speaking, that dog ownership is good for you. For these and other reasons, Kazi concludes that

"the association between dog ownership and improved survival is real, and is likely at least partially causal."

One final question is still nagging at me, though. Now that we know that dog ownership is good for your health, what's the optimal dose? Would it be even healthier to own two dogs rather than one? And what if we throw in a cat, does that strengthen or reduce the effect? Finally, is it healthier to own a larger dog, or is a small one just as good?

Clearly, more research is needed.

[Note: the author discloses that he owns a rescue dog, a rather small terrier.]