It might be healthier to run a mile than a marathon

Training for a marathon may not be the best way to get fit in 2018.
Shorter bursts of high-intensity exercise can confer some of the same health benefits as long-distance running.
One of the most popular forms of this workout is called 'interval training,' or HIIT.

If completing a marathon is on your list of New Year's resolutions for 2018, you might want to think again.

As it turns out, that intense feat of human endurance may not be the most efficient ticket to a healthier you. Instead, a regular fitness routine focused on short intense workouts may confer faster results.

That wisdom appears to apply not just to running, but also to a variety of heart-pumping workouts that fall under the umbrella term of "interval training."

Quick bursts of exercise carry some of the same benefits as longer workouts

Interval training "can provide similar or greater benefits in less time than traditional longer, moderate-intensity workouts," Chris Jordan, the director of exercise physiology at the Johnson & Johnson Human Performance Institute, told Business Insider in April.

One of the most popular forms of this style of workout is high intensity interval training, or HIIT. It's also the form of training that has been studied the most.

High intensity interval training involves committing to short bursts of sit-ups, jumping jacks, or planks performed at your maximum capacity. After each 30- to 45-second interval, you rest to catch your breath and then move on immediately to the next exercise. At the end of the workout (which could be as short as seven minutes), your whole body should feel it.

Tabata training, named after the Japanese National Institute of Fitness and Sports researcher Izumi Tabata, is an HIIT workout made up of several four-minute exercises. Tabata and his team became some of HIIT's pioneers after publishing a seminal 1996 study suggesting that short bursts of intense strength training could have better results than a traditional workout.

The principal behind interval training isn't limited to push-ups and jumping jacks, though — it also applies to classic forms of exercise like running and walking.

For a recent study, a large group of daily runners were split into two smaller groups — one that ran less than an hour each week and one that ran more than three hours per week. At the end of the study, the group of daily runners who only spent an hour running each week saw almost the same heart health benefits as those who ran for more than three hours.

A 2012 study comparing a group of runners who did traditional, continuous runs with a group of runners who did interval training found that both groups achieved nearly the same results. There was one small difference, though: The interval trainers had better peak oxygen uptake, an important measure of endurance.

Additionally, a recent study in the journal Diabetologia found that doing walking interval training — an hour of alternating between three minutes of brisk walking and three minutes of stopping — helped people with diabetes control their blood-sugar levels far better than simply walking at the same pace continuously.

More is not always better when it comes to fitness

Unlike shorter jogs and interval training plans, distance running comes with some serious health risks.

There's some evidence to suggest that prolonged, intense exercise — such as the type necessary in the weeks and months before a marathon and during the race itself — can have some unhealthy side effects, from reduced immune function to digestive issues.

Working the body to its maximum, some research shows, can reduce the body's natural ability to fend off upper-respiratory infections including colds and the flu. Short bouts of activity, on the other hand, improve immune function. Quick workouts appear to not only reduce your chances of getting sick, but also to reduce the severity of an illness when you do come down with something.

Up to 71% of long-distance runners experience abdominal cramping and diarrhea as well. (The latter is so frequent that runners have a term for it: "runner's trots," also known as "runner's diarrhea.") Many runners also experience acid reflux — a condition with symptoms like heartburn, indigestion, coughing, hoarseness, and asthma — during and immediately after a long run.

So if running marathons isn't your thing, try a shorter, daily exercise plan — but make sure that whatever regimen you choose is one you can keep doing regularly.