Khloé Kardashian always keeps her social media followers up-to-date on her latest fitness obsessions, whether she's posting her daily workout routine on Instagram or sharing her gym bag essentials on her official app. Yesterday, the Keeping Up With the Kardashians star, 33, took to Snapchat to reveal her current must-have piece of workout equipment: an upgraded version of the classic foam roller.

In a series of snaps, Kardashian raved about her HyperIce Vyper 3 Speed Vibrating Foam Roller ($179, amazon.com), saying she uses it after many different workouts. And if the name doesn't make it clear, yes—this foam roller vibrates.

RELATED: Can Foam Rolling Really Get Rid of Cellulite?

At first glance, you might not even realize that the HyperIce Vyper is a foam roller; the sides feature buttons and lights that make it look more like a boom box than workout tool. But with three different vibration speeds, it claims to combine the practice of foam rolling with vibrating technology to relieve muscle pain and stiffness.

Kardashian isn't the only HyperIce Vyper fan. The product has over 150 customer reviews on Amazon, and 70% of reviewers gave it a 5-star rating. Many of those reviews echo the reality star's claim that the vibrating tool comes in handy after many different workout routines, from running to HIIT to yoga.

"This thing was sent by the workout angels," says Amazon user Mark Aardvark.

Experts agree that foam rolling can deliver some real benefits. "There's ample evidence that this kind of massage helps boost tissue repair, increase mobility, and decrease soreness," Kari Brown Budde, DPT, a sports physical therapist in Columbus, Ohio, told Health in a previous interview.

But if you're not willing to invest nearly $180 in the vibrating version, the good news is that even more basic foam rollers can help soothe knots and relieve post-workout muscle pain. We like the RumbleRoller ($80; amazon.com) and the super-portable SKLZ Hydro-Roller ($38; amazon.com). Try foam rolling everywhere from your shins to your glutes to your IT band for full-body pain relief.

This article originally appeared on Time.com.

Even Hippocrates believed that the changing seasons had something to do with health—and that the key was how much available daylight there was during different times of the year.

Many centuries later, it’s clear he was onto something. As people spend more time indoors staring at computer and television screens, scientists are starting to appreciate how exposure to sunlight affects various body systems.

The most interesting support for our dependence on daylight emerged with a condition called Seasonal Affective Disorder, or SAD. The term was coined by Dr. Normal Rosenthal at Georgetown University to describe the so-called winter blues: the lethargy and feelings of sadness and hopelessness that come when the weather forces people to spend more time indoors and the season provides little opportunity for exposure to natural light. Some people have speculated that our modern lifestyle, which keeps people indoors under artificial light for so many hours, may be encouraging a form of SAD year-round.

Rosenthal found that while not everyone is as strongly affected by a lack of sunlight, for the people who are, light boxes that blast a few minutes of bright light in the frequency of natural sunlight each morning can help to elevate mood and re-energize them to face the day.

Studies of shift workers also support the possible role that exposure to sunlight has on mood. Messing up the normal light and dark cycles by sleeping during the day and being awake at night, under artificial light, can disrupt the body’s metabolism. That can have domino effects on nearly everything: how we break down energy from food, how strong our immune systems are and the vast array of brain chemicals and other substances that contribute to mood, weight, energy and more. People who consistently work night shifts, for example, tend to be heavier than people who don’t.

There is also intriguing evidence finding that people who work at night and don’t get exposed to daylight may produce less melatonin, a hormone that is dependent on light. Normally, people produce more melatonin toward the evening, as the body gets ready for sleep. As more light creeps in during the morning, the levels of the hormone start dropping again. In winter months when the days are shorter, melatonin levels may peak earlier or later in the day, which can lead to some of the mood changes linked to SAD. Studies in shift workers found that less melatonin may also lead to lower levels of important chemicals the body uses to repair DNA. That could potentially lead to more mutated cells that can trigger cancer.

Some studies also suggest that the light cycle may regulate the production of blood stem cells from the bone marrow. More research here is needed, but that could be important for the timing of bone marrow transplants for cancer patients, and hitting the transplant at just the right time of the light cycle may improve the chances of harvesting enough cells from donors…

This article originally appeared on DailyBurn.com.

Considering HIIT — or high-intensity interval training — is known to burn fat, improve metabolic health and increase VO2 max levels, you may have jumped on board enthusiastically. After all, it’s known to fire up your gains rather quickly and efficiently. “People like HIIT because it removes one major barrier to not working out: ‘I don’t have time,’” says New York City-based fitness coach Laura Miranda, DPT, CSCS.

HIIT involves alternating between “work” intervals of high intensity with “recovery” or rest periods of lower intensity. Most HIIT workouts call for work periods of 20 to 30 seconds (even up to 90 seconds), explains Craig Weller, exercise specialist at Precision Nutrition. The work to rest radio may be 2:1 (like in a traditional Tabata-style workout), 3:1, 1:2 and so on, he says.

No doubt HIIT is one amazing workout, but there are some aspects of the workout that you may be doing wrong. These mishaps could sabotage your efforts and diminish your results. Here’s how to ensure you get the calorie-torching sessions right.

RELATED: HIIT It Hard with These 25 Workouts and Tips

7 Mistakes That Are Hurting Your HIIT Workout

1. Failing to Warm Up

HIIT is demanding, and it’s not a good idea to pop into the gym right from bed or immediately after sitting for a full day. “At that time, your neuromuscular connections are not firing as well as they should be,” says Miranda. If you skip the warm-up, you may only be able to push at max effort, starting halfway through the workout. (Womp, womp.) Prepare your body with dynamic functional movements that are similar to the moves you’ll do in a workout. For example, slow and controlled side lunges in prep for skater jumps.

RELATED: The Dynamic Warm-Up You Aren’t Doing (But Should!)

2. Planning Long Workouts

When done correctly, a HIIT workout doesn’t have to be long — it can actually last anywhere from four to 20 minutes, says Weller. Miranda caps her clients at 30 minutes per HIIT routine. The catch: You shouldn’t be able to do more than that if you’re truly pushing yourself during the “working” intervals. Schedule a longer workout and you’ll likely hold yourself back during the intense pushes in order to conserve energy. “At a point, you’re getting diminishing returns. You’ll be working out longer but not as efficiently,” says Miranda. Don’t you want to spare a few minutes with HIIT, anyway?

3. Not Going Hard Enough

During the intense intervals, “science shows that you have to push at 80 to 90 percent of your max heart rate to achieve results,” says Miranda. If you don’t have a heart rate monitor, think of this on a rate of perceived exertion scale (or RPE), meaning how hard you feel like you’re working…