Fitness trainers get asked all of the time whether doing cardio or weight training first is best. Now that it's well accepted that both cardio and weight lifting are important and beneficial activities for everyone, people are confused as to whether they should be doing one particular exercise before the other.
Should you hit the weights first? Or the treadmill?
Fitness experts are often split on the answer. What isn't disputable is that you will have the energy to perform at a higher level during whichever activity that you choose to do first.
For most of the general population, that means it's best to begin a workout with...
For Most: Do Weight Training First
Your exercise performance will suffer during whichever activity you do second, which is why in most cases you should lift weights first.
Research has shown that when you lift weights before you do cardio:
1. You'll Maximize Your Weight Lifting Workout
When people do their cardio sessions first, they complete fewer reps during the weight-training component. Because of the neurological and muscle fiber fatigue following aerobic exercise, as you go to lift weights your muscles are unable to produce as much power or force. Your form will likely suffer, increasing your risk of injury. You don't lift as much weight or do as many reps, which means you don't get the most out of your training.
Lift weights before cardio, however, and you'll have the strength and power to lift heavier loads, which in turn will help you become stronger and put on more lean muscle.
2. You'll Burn More Overall Fat
Lifting before you do cardio could also help you burn more calories during your cardio component. One study found that doing cardio after lifting increased the amount of fat burned during the first 15 minutes of the cardio session. This is because you burn through your glycogen stores during your lifting workout, forcing your body to break down and use stored fat as fuel during cardio.
Additionally, lifting first can mean a bigger boost to your metabolic rate. Following high-intensity weight training workouts, your body has to work to restore itself to a resting state. It rebalances your hormone levels, replenishes your glycogen stores, and repairs your damaged muscle fibers. This process, referred to post-exercise oxygen consumption (EPOC) can take a couple days and requires fuel, so you end up continuing to burn more calories for up to 48 hours. EPOC occurs at a higher rate following weight lifting workouts that are of a high intensity, so the fresher you are going into a lifting workout, the greater boost to your metabolic rate and the more calories you burn.
Other Considerations: Your Training Goal and Motivations
There are acceptations to the recommendation to lift weights first. Depending on your training goal, doing cardio first may be a better option.
If you're a competitive endurance athlete, such as a marathon runner or a long-distance cyclist or swimmer, your cardio training is the bread and butter of your regimen. During your running, biking or swimming training, you're likely focusing on mastering technique and conditioning. You therefore want to be as fresh as possible for your cardio work.
The same idea applies to sport athletes, like basketball players. You wouldn't want to fatigue your muscles with weight lifting before practice because you could adversely affect your shooting, passing or dribbling techniques. While weight lifting is beneficial for endurance and sport athletes, it's best to strength train at the end of the day so that they're fresh during their cardio or sport training session.
It may also serve you best to finish your workout with the activity that you enjoy the most. If you simply can't stand cardio, you may find yourself wanting to cut your workout short if you leave it for the end. So if you love lifting weights but struggle through completing cardio, you may want to leave weight lifting for the end so you know you'll still have the motivation and drive to finish the workout once fatigue kicks in.