When it comes to structuring a workout routine, the debate over whether cardio should come before or after weight training has been a long-standing topic among fitness enthusiasts. Depending on your fitness goals—whether you're looking to burn fat, gain muscle, or enhance endurance—the answer can vary. However, understanding the science behind the combination of cardio and weight lifting can help you make an informed decision on the optimal order for your workouts.Before delving into which should come first, it's important to recognize the benefits of both forms of exercise. Cardio, often seen as the go-to activity for weight loss, is effective at burning calories and improving cardiovascular health. Weight training, on the other hand, builds muscle mass, increases strength, and contributes to fat loss through muscle growth, as muscle burns more calories even at rest. When combined, these two forms of exercise can enhance each other, improving overall health, fitness, and body composition.A study published in the Journal of Gerontology found that long-term aerobic exercise is linked to greater muscle strength over a lifetime. Meanwhile, strength training also aids endurance athletes, as research from the University of Oklahoma suggests that lifting weights can improve VO2 max—the maximum rate at which your body can use oxygen during intense activity.Both cardio and weight training are essential for well-rounded fitness. In fact, a 2022 study from the British Journal of Sports Medicine found that those who incorporated both cardio and strength training into their routines had a significantly lower risk of mortality than those who only focused on one. The key, then, is not necessarily choosing one over the other but understanding how to combine them effectively based on your personal fitness goals.Should You Do Cardio Before or After Weight Training?The answer to whether cardio should come before or after lifting weights isn't as clear-cut as many may hope. According to the American Council on Exercise (ACE), the best order depends on what you're trying to achieve in your fitness journey.For endurance: If your goal is to improve endurance and cardiovascular health, doing cardio before weights may be more effective. Starting with cardio when your energy levels are highest allows you to perform at your best during the run, bike ride, or swim. For weight loss and fat burning: On the other hand, if your goal is to shed fat, it’s often recommended to do cardio after strength training. Weight lifting depletes glycogen stores in muscles, making it easier for the body to burn fat during cardio. This combination promotes the "afterburn" effect, where the body continues to burn calories even after the workout is over.For muscle gain and strength: If building muscle and gaining strength is your primary focus, weight training should come before cardio. Starting with weights ensures that you’re fresh and can lift the heaviest loads with proper form, maximizing strength gains.For general fitness: If you don’t have a specific goal in mind but just want to stay fit, doing either cardio or weights first can work. It might be a good idea to start with the exercise you enjoy less, or the one that challenges you the most.But Why Weights Should Typically Come Before CardioAlthough the debate continues, there are several compelling reasons to prioritize weight lifting over cardio. One key factor is energy—lifting weights demands significant strength and mental focus. If you perform cardio first, especially high-intensity cardio, you may exhaust your energy stores, making it harder to push through a solid strength workout. As a result, your lifting session might suffer, and you could risk poor form or even injury.A Journal of Strength and Conditioning Research study confirmed this by showing that strength training performance declined when participants did cardio first. In contrast, when strength training was done first, participants were able to complete more repetitions with better form.Additionally, when you lift weights first, you maintain the intensity needed to push your muscles to fatigue, which is essential for muscle growth. If you prioritize weight training, you're more likely to achieve better results in terms of building muscle mass, increasing strength, and burning fat through an increased metabolic rate.How to Balance Cardio and Weight Training For Best Results?One of the most effective ways to add both cardio and weight training into your fitness routine is by separating them on different days. This allows you to dedicate more energy and focus to each activity. For example, you could alternate between cardio-heavy days (running, swimming, cycling) and weight-lifting days to allow sufficient recovery time for your muscles.However, if you're pressed for time or prefer to complete both activities in one session, it's important to listen to your body and experiment with what feels best. Start with either cardio or weights and assess how you feel throughout the session. Does your energy flag too quickly during your lifting session after a cardio workout? Or do you find your cardio performance lacking when you lift first? Through trial and error, you can determine what works for you.How Often Should You Combine Cardio and Weight Training?For a balanced fitness routine, the U.S. Department of Health and Human Services recommends that adults engage in at least 150 minutes of moderate-intensity cardio or 75 minutes of vigorous-intensity cardio per week, coupled with strength training at least twice a week. Strength training exercises should target all major muscle groups. If muscle building is your focus, consider increasing weight training to three times a week for optimal results.In the end, whether cardio should come before or after lifting weights depends on your individual fitness goals. Both forms of exercise have their place in a well-rounded workout regimen, and finding the right balance between the two can make a significant impact on your fitness results. Remember that consistency is key—no matter the order in which you perform your exercises, the most important factor is making both cardio and strength training a regular part of your routine. Long-term aerobic exercise is associated with greater muscle strength throughout the life span. J Gerontol A Biol Sci Med Sci. 2013Dose–response association of aerobic and muscle-strengthening physical activity with mortality: a national cohort study of 416 420 US adults. BMJ. 2014Acute Effect of High-Intensity Aerobic Exercise Performed on Treadmill and Cycle Ergometer on Strength Performance. Journal of Strength and Conditioning Research. 2015