It's the time of year for self-improvement. But if getting healthy is on your list of ways to be a better version of yourself, know this: It doesn't necessitate grand efforts. Here's what science has to say regarding how little effort you can expend to hone your body and feel better.

Getting stronger only takes 13 minutes, three times a week

That's according to a study recently published in Medicine and Science in Sports and Exercise. Researchers split 34 fit male participants into three groups and had them do five, three, or one set of several common weight lifting exercises. Respectively, this took 70 minutes, 40 minutes, and 13 minutes a session. They did the same workout three times a week for two months and all three groups showed significant--and similar--gains in strength. So, why push yourself for over an hour to get stronger, when only 13 minutes has the same effect?

The findings jibe with high-intensity, slow-motion training I've done, which leaves a person feeling like jelly at the end of a 20-minute workout. The only catch is that the one set must be done to failure, meaning you physically cannot perform one more repetition at the end. To make it happen, just make sure you're lifting enough weight and doing it slow enough so your muscles are exhausted by the tenth to twelfth rep.

You can improve your body's function and alleviate anxiety in two minutes a day

According to experts interviewed by Amanda Arnold of The Cut, most people deal with a constant state of low-level stress, thanks to work and financial pressures, the hassle of commuting, or too few in-person interactions with friends and family. As a result, the body is often in a state of alert, which increases heart rate, blood pressure, cortisol, and adrenaline levels, not to mention the uncomfortable feelings of anxiety.

Yet fixing this uncomfortable state of physical and emotional affairs is remarkably easy. Deep breathing stimulates the vagus nerve and the parasympathetic nervous system to reduce the heart rate, decrease blood pressure, and increase the alpha brain waves involved in feelings of relaxation. And a once- or twice-daily habit of breathing in for four seconds and out for eight seconds--for only two minutes--can prevent your stress response from turning on in the first place.

Cutting out sugar is the easiest way for most people to have better health and live longer

According to biochemist and scientist Dr. Rhonda Patrick, speaking on the Tim Ferriss Show podcast, refined sugar kills countless people annually by contributing to diabetes, cardiovascular disease, and cancer. And if it doesn't kill you, it will likely reduce your lifespan. It's remarkable to look at what researchers have found about soda alone:

Healthy adults that drink 12 fluid ounces (or roughly a can) of soda per day had much shorter telomeres in their white blood cells than people the same age who do not drink soda every day, a reduction in telomere length roughly equivalent to 4.6 years of biological aging. Telomere length is a well-established biomarker for aging since our telomeres get shorter every year...and for that reason, it should be at least a little alarming when you see an amount that is equivalent to 4.6 years of aging getting trimmed off. Inflammation, one of the factors that is very important to aging, may also be at play here. One trial found that giving healthy, normal-weight young men 20 ounces of a sugar-sweetened beverage that was more or less similar to drinking a similar amount of soda daily for three weeks was enough to trigger an increase in the biomarker of inflammation C-Reactive Protein between 60 percent to 100 percent higher levels than they started with. What about hormones? In one study, men experienced a 25 percent decrease in testosterone for up to two hours after 75g of sugar intake.

She says sugar also affects the brain similarly to substance use drugs in that it lights up the brain's reward system, so that people crave it and need more and more sugar to get the same effect. "You will be so much healthier by just cutting out this one thing," she says. "Once you stop eating refined sugars, foods begin to actually taste sweeter. That's a real effect that's been shown in clinical studies."