For a Healthier Heart, Just Combine Them
One of the biggest hurdles for many people is simply finding the time to exercise. If your main goal is improving your overall cardiovascular health, recent findings bring great news. A large, long-term study from Iowa State University found that splitting
your workout time equally between aerobic activity and resistance training can reduce your risk of cardiovascular disease just as effectively as doing aerobic exercise alone. This means you don't have to choose one over the other to reap significant heart-healthy rewards. For those bored with endless cardio or who have joint issues that make long runs difficult, this combined approach offers variety and the unique benefits of both exercise types, like building strength and preserving muscle.
To Maximise Strength, Lift Weights First
If your primary goal is to get stronger or build muscle, the science is becoming increasingly clear: resistance training should come before cardio. A recent study published in the Journal of Exercise Science & Fitness confirmed this by showing that participants who lifted weights before their aerobic session saw greater improvements in both maximum and explosive strength. The logic is simple. Weightlifting requires focus, energy, and maximal muscle recruitment. When you perform cardio first, you deplete your muscles' primary fuel source—glycogen—and induce fatigue. Trying to lift heavy weights with a pre-fatigued body not only reduces your performance, meaning you can't lift as much, but it can also compromise your form and increase the risk of injury.
The Surprising Order for Fat Loss
For many, the main reason for exercising is to lose fat. Here too, the 'weights-first' approach seems to have an edge. The same study that highlighted strength benefits also found that the group performing resistance training before cardio lost significantly more body fat, particularly the dangerous visceral fat that surrounds your organs. While overall calorie expenditure is crucial for weight loss, the order seems to play a key role. Lifting weights helps to build and preserve lean muscle mass. The more muscle you have, the higher your resting metabolic rate, meaning your body burns more calories even when you're not exercising. Starting with strength training ensures you have the energy to build that metabolic engine before you burn calories with cardio.
When Cardio Should Take the Lead
Of course, there are exceptions to the rule. If your goal is endurance-based, such as training for a 10K run, a marathon, or a cycling event, it makes sense to prioritise cardio. In this scenario, you want to tackle your main activity with the most energy and focus. Doing your run or ride first ensures that your performance isn't hampered by muscle fatigue from a prior lifting session. Research shows that performing an intense cardio session after strength work can force your heart to work harder for the same result, potentially undermining your endurance training goals. After your main cardio workout, you can then perform supplementary strength training, which is still incredibly beneficial for endurance athletes by improving running economy and reducing injury risk.
Understanding the 'Interference Effect'
The science behind this advice often comes down to something called the "interference effect." In simple terms, your body has different signaling pathways that get activated by different types of exercise. Strength training activates pathways that promote muscle growth (like mTOR), while endurance exercise activates pathways that boost aerobic fitness (like AMPK). The issue is that the endurance pathway can sometimes block or dampen the muscle-building pathway. For elite athletes or those trying to maximise every last bit of muscle gain, this interference is a real concern. However, for most people pursuing general fitness, the effect is less dramatic. The key takeaway is that separating intense cardio and heavy lifting—either by doing them on different days or by putting at least a few hours between them—can help you get the best of both worlds.
