Summer is right around the corner, which means your gym is probably packed to the gills with people who put off their New Year’s resolution until the weather got a little warmer. As you get your own beach body ready for the warm summer months, you may be wondering where you should place the majority of your focus: cardio or weightlifting. Before you decide which type of activity your workout routine will emphasize, it's best to know how much goes into this decision.

Cardio and weightlifting are an integral part of any successful fitness program, along with nutrition, of course. Balancing cardio with weightlifting is a tricky endeavor. It generally comes down to tailoring the amount of cardio you do to the amount of weightlifting. The effect cardio or weightlifting has on your physique is dependent on a variety of factors, including how much cardio or weightlifting, what types of cardio or weightlifting, what you’re eating, what your fitness goals are, and your body type.

“Running, cycling, and aerobic classes are examples of cardio,” Donovan Green, celebrity fitness trainer and author of No Excuses Fitness, told Medical Daily. “Cardio aka cardiovascular exercise gets your heart rate up and gets more oxygen pumping through your blood. There are big health benefits regarding cardio training, including improved circulation, it increases bone density, improves sleep, reduces anxiety, and gives you increased energy. With strength training, you are switching on more of your muscle fibres and raising your metabolism so there's more active tissue in your body. You are burning calories when sitting down after your workout.”

Weight Loss

If you’re thinking about foregoing any weightlifting or resistance training while focusing solely on cardio, then check out the physique of any long-distance runner and you’ll see what road you’re heading down. For anyone looking to take the opposite approach by foregoing cardio, don’t expect to meet any weight loss goals, especially if your body type is endomorph, meaning your body retains fat and has a harder time dropping it.

Finding the correct balance between cardio and weightlifting is all about experimentation. For example, start off with four days a week dedicated to an hour of weightlifting and the remaining three days dedicated to 30 minutes of cardio. Tailor this routine to how much energy you’re expending each day, your progress after around a month, and what you would like the final result to be.

A recent study conducted at the Duke University Medical Center revealed that a healthy combination of aerobic and resistance training is the best formula for reducing body fat and increasing lean body mass. Out of 234 formerly sedentary overweight and obese adults, those assigned to the aerobic plus resistance training group were able to not lose more weight, while also gaining more lean body mass.

Building Muscle 

One of the most common misconceptions every gym rat struggles with is the notion that cardio will diminish the effect of strength training by hindering muscle growth. People with an ectomorph body type, someone with a naturally slim physique who finds losing weight easier than most, are often fooled into abandoning cardio due to this rationale. While the amount of cardio needed to lose weight is clearly more than the amount needed to build muscle, cardio is still necessary to build your ideal physique.

Deciding on a healthy medium between too much and too little cardio leads most fitness fanatics to one of the hottest exercise crazes today: high-intensity interval training (HIIT). Instead of jogging around a track for an hour at a moderate pace, alternate between intense periods of activity and slower recovery intervals. HIIT is heralded for kicking up your body’s ability to burn calories during a workout as well as when the body is resting, also known as “afterburn.”

“Another great benefit of weight training is you can get two for the price of one,” Green added. “Doing circuit training with weights will not only boost your strength it will also increase your cardiovascular system. A quick example would be deadlifts, front squats, benchpress, and lat pulls. Complete each move for 30 seconds. And repeat for a total of four rounds.” 

Heart Health

Of course, being physically active isn’t always about shaping the perfect beach body. Sometimes a workout plan is necessary to improve or preserve a person’s cardiovascular health. Cardio may be short for cardiovascular, but strength training still has its place in any heart healthy workout plan. In fact, too much cardio could potentially have a damaging effect on the heart.

Research published in the European Heart Journal measured the cardiac enzymes and conduct ultrasounds on 40 long-distance runners who had recently competed in four endurance races. After each long-distance competition runners often suffered from right ventricular (RV) dysfunction, increased blood levels of cardiac enzymes — often a marker for heart problems — and 12 percent of runners even experienced scar tissue in their heart muscle that discovered a week after the race via MRI.

“Cardio in the light to moderate intensity range stimulates the body to increase overall blood volume, thereby increasing the amount of red blood cells if the behavior is maintained for over a month (the time it takes to remake blood cells),” Joey Gochnour, registered dietitian nutritionist and certified personal trainer, told Medical Daily. “It is helpful for reducing blood pressure acutely. Cardio in the light to moderate intensity range also creates adaptations in the peripheral cardiovascular system, such as increasing capillary density and overall efficient circulation.”