Need extra motivation to get to the gym or to go for a hike today? A study in the Archives of Internal Medicine followed over 2,000 twins for a year and discovered that the DNA of the active sibling (90 minutes of vigorous exercise a week) appeared four years younger than the DNA of the sedentary sibling.

So the May issue of Shape concludes that “for every minute you sweat it out per week, you can take about 16 days off your age.” Ok, let’s calculate this. Take the number of minutes you work out per week on average (say 3 hours a week or 180 minutes) and multiply that by 16 (days). Divide that number (2880 in this case) by 365 (days in a year) to find out how many years younger you are thanks to your active lifestyle. In this example it’s 7.89 years! Pretty impressive, but remember that in reality there are a bunch of other factors that affect aging as well. For a better calculation on how your good and bad health habits affect your age, take the Real Age test.

Here’s a killer ab exercise from Shape’s Best Tested Ab Moves Workout: The Bridge with Leg Extension.

Lie on your back with your knees bent and both feet on the floor. Anchor yourself with your hands at your side. Pull your navel toward your spine, contracting your abs. Lift your body up so only your shoulder blades are touching the floor, making sure your body forms a straight line. Hold this pose for 30 seconds.

Then, while you’re still in the lifted position, extend your left leg out at hip height. Hold, then switch to lift your right leg, keeping your hips elevated the whole time. Alternate back and forth 8 times. Rest, then do another set. You’ll feel the burn in your abs (including your obliques) and lower back.

Lately I’ve had a lot of people asking me questions about how many calories you should be eating each day and how to determine ideal body weight. Well, I’ve searched the Web and came up with a few great tools you can use to get all the numbers right.

Ideal Body Weight

Daily Calorie Needs

Daily Protein Needs

Body Mass Index (BMI)

Target Heart Rate Calculator

If you don’t see a tool for everything you’re wondering about here, let me know and I’ll hunt down the best calculator for you.

Here’s one of my favorite ab moves that has stood the test of time in my arsenal of abdominal exercises. I first learned this in kickboxing back in college, but it works so well that I still do it today.

Start with your feet flat on the floor and lean back until you start to feel your abs working. Punch your right fist toward your left knee as you twist slightly to the left. Reverse to punch your left fist toward your right knee as you twist slightly to the right. Repeat 12 times. Do three sets. You’ll work your entire core, especially your obliques.

For an added burn, lift you feet off the ground so you’re balancing on your sit bones. Pick up your pace to double time–twist and punch left to right until you have to stop.

I took a one-on-one yoga class last weekend. Throughout our practice my instructor kept reminding me to focus all of my attention on the part of my body where I felt it most. So when I was in a super challenging pose that required a lot of strength–I focused not only on my breath, but also on the muscle or muscles that were working the hardest. Or if I was doing a stretch that was particularly hard, I’d focus on the least flexible point to get deeper into the pose.

This is a good philosophy for any kind of training, not just yoga. Studies have shown that if you focus intently on flexing your bicep during a curl, you’ll work harder to build that muscle than if your mind wanders. And it’s certainly more productive to think about the area you need work than the difficulty of the work. So next time you’re trying to get through the last few reps of weight lifting or the last few minutes of an activity, bring all of your attention to that hard working muscle and see if you can push yourself that extra step.

Have you ever wondered what you’re supposed to do with those foam rollers in the gym? For one, you can use one to give yourself a massage. If your muscles are tight, say your quads, you can lie on the foam roller and slowly roll your body back and forth along the roller to work out the kinks. When you get to a knot, you can stay put until the pressure eases and then continue rolling.

But if your muscles are feeling fine, you can use rollers to add instability and variety to strength building moves. Here are a couple ideas from Diet.com.

I took a new class the other day that incorporated the Body Wedge–basically it was sculpt on an angle. The Wedge is like an incline bench except it’s made out of soft foam material which adds a challenging level of instability (and it’s more comfy to lay on!). With it, you can work pretty much every muscle in your body (back, butt, triceps, shoulders, etc.)

During the class we stood and sat on the wedge, lifting weight with dumbbells and body bars. We also laid on it for ab work. If you’ve ever done ab exercises on the incline bench after months of doing crunches on the ground or tried lifting weights while standing on the Bosu, you’ll know what I mean when I say the extra incline and instability really helps you feel the burn!

The Wedge didn’t seem like a dramatically different fitness tool, but it will work your muscles in different ways, so try it the next time you want to mix up your strength routine.

In honor of Earth Day, try an activity that’ll help save the planet and burn calories all at the same time. These estimates are based on a 145 pound person.

Bike to and from work: If your round trip ride takes an hour, your commute is worth 526 calories.

Spend two hours tending to your organic garden: Bend, squat, dig, rake and water to burn off almost 600 calories.

Recycle: Spend 20 minutes sorting glass, cans, plastic and paper, then take it all to the curb or recycling center to zap 93 calories.

Walk to and from the farmer’s market: If your entire shopping excursion takes an hour, you’ll burn 205 calories thanks to your walk and toting around that big bag of fresh fruits and veggies.

Plant trees for an hour: Lift, squat and dig your way through 313 calories.

I’m jetting off to the Dominican Republic later this week and since it’s a last minute trip, I haven’t had a whole lot of time to get ready for my bathing suit. But here are three ways that I’ve been trying to get ready fast. Try these tips for quick results before your next beach escape.

1. Give your workouts extra oomph: If you run 3 miles, run another mile of interval sprints. If you like to take a sculpt session, hit the stair climber for 15 minutes after class. If you have a strength training routine, add plyometric bursts in between sets instead of resting.

2. Eat whole foods: Choose veggies, legumes and proteins like chicken or fish, to avoid extra sugar, fat and sodium. Processed, frozen, canned and restaurant meals can harbor a lot of hidden diet downfalls. Cutting back on salt can help you look and feel thinner quickly because sodium makes your body retain fluids. Get super serious a couple of days before you bare your bikini. Pay close attention to sodium levels on nutrition labels–you may be surprised how much you’ll find even in condiments like ketchup. Try to keep your sodium level under 500 mg a day.

3. Get a bronzed bod: I don’t know about you, but I feel more toned with a bronze glow than when I’m pastey white. I’m not telling you to visit your tanning salon for a fake bake, but I do advocate swapping out your normal body lotion for a tan-building variety like Dove Energy Glow.

Here’s a move from Women’s Health that I tried the other day. The added weight will definitely have you feelin’ the burn. This move works not only your abs, but also your hips and upper back.

Start lying on your back with a set of 10- to 12- pound free weights.

Raise your legs to a 45-degree angle with your arms over your head to get to the starting position shown in image A.

At the same time, lift your legs until they’re perpendicular to the floor and reach your arms over your chest and toward your toes, lifting your shoulders off the floor.

Return to the start, never letting your legs touch the floor and continue for 3 sets of 15 reps.