The role of cardio in weight loss is a frequently debated topic, often leading to confusion for individuals seeking to manage their weight. Experts clarify that weight loss involves various exercise modalities, with cardio playing a crucial part by increasing total daily energy expenditure, thereby contributing to the caloric deficit necessary for weight reduction. Rachelle Reed, PhD, an exercise physiologist, emphasizes this point. Simultaneously, resistance training is highlighted as an arguably more critical component, as it not only burns calories during a workout but, more significantly, preserves or builds lean muscle mass. This muscle mass, in turn, supports a higher resting metabolic rate, meaning the body burns more calories even at rest over time.

Disha Narang, MD, an endocrinologist and director of obesity medicine, reinforces that while cardio is important for weight loss, it is just one element of a larger strategy. The most sustainable and significant changes in body composition typically occur when cardio is integrated with strength training and a balanced, calorie-appropriate diet. Dr. Narang explains that while cardio provides immediate calorie burning, strength training fundamentally alters the body's metabolism by building muscle, leading to increased calorie expenditure around the clock.

Recent research supports the efficacy of aerobic exercise. A 2024 meta-analysis published in Jama Network, involving 116 randomized clinical trials and 6,880 adults, found that at least 150 minutes of weekly aerobic exercise was linked to clinically significant reductions in waist circumference and body fat. Increasing this to 300 minutes per week correlated with even greater reductions in body weight, waist size, and overall fat metrics. While this specific analysis did not delve into resistance training, the combined benefit of muscle-building activities and cardio for maximal weight loss success is acknowledged.

Regarding the "best" type of cardio for weight loss, experts agree there isn't a universal answer. Dr. Reed suggests that the most effective form of cardio is one that an individual enjoys, can perform consistently multiple times per week, and can progressively challenge over time. Examples include steady-state cardio, which is generally easier to sustain and recover from, walking for its accessibility and potential for high weekly volume, and high-intensity interval training (HIIT), which is time-efficient but may not suit everyone. Dr. Narang advises prioritizing enjoyment and consistency, pairing any chosen cardio with a balanced diet. She stresses that nutrition is the primary driver of weight change, noting that a structured, protein-rich diet with limited processed foods surpasses exercise alone for fat loss and muscle preservation. A 2025 meta-analysis in Nutrition Reviews further supported this, concluding that dietary interventions combined with high-intensity aerobic exercise, particularly cycling, were crucial for mitigating metabolic risk in overweight or obese individuals.

It is also possible to overdo cardio, which can inadvertently hinder weight loss efforts. Excessive cardio can reduce training quality, elevate stress levels, and increase the likelihood of injury, all of which decrease overall physical activity and energy expenditure. Without adequate recovery, high volumes of endurance exercise can lead to overtraining syndrome, manifesting as impaired performance, increased fatigue, mood alterations, and hormonal imbalances, according to 2022 research in Frontiers. Dr. Reed emphasizes the importance of striking a balance: enough intensity to stimulate adaptation without undermining recovery, strength training quality, or long-term consistency. Furthermore, excessive cardio should not displace resistance training, as muscle is metabolically active tissue, and its loss due to cardio-only programs can slow progress over time. Strength training is vital for metabolic resilience and long-term weight maintenance.

To effectively incorporate cardio for weight loss, the American College of Sports Medicine recommends 150 to 300 minutes of moderate-intensity aerobic activity or 75 to 150 minutes of vigorous-intensity aerobic activity per week. However, the optimal approach is to integrate cardio into a holistic routine that includes strength training two to three times a week to preserve lean muscle mass. Dr. Narang metaphorically refers to cardio as the "energy burn" tool and strength training as a "metabolic investment." For weight loss, she recommends three cardio sessions (30-60 minutes each, mixing steady-state and intervals), two to three strength training sessions (30-45 minutes each, full-body exercises with 6-8 exercises, 2-3 sets, 8-12 reps), and one active recovery day (45-60 minutes of gentle movement like walking or yoga) per week.

Achieving a calorie deficit for weight loss can be done by reducing intake, increasing expenditure through exercise, or a combination. The American Council on Exercise provides a guide to high calorie-burning exercises (estimated for a 125- to 185-pound person): jumping rope (667–990 calories/hour at 120 skips/min), running sprints (639–946 calories/hour), kickboxing (582–864 calories/hour), indoor cycling (568–841 calories/hour), running (566–839 calories/hour at 10-min mile pace), kettlebell circuits (554–822 calories/hour), rowing (481–713 calories/hour at 150 watts), and stair climbing (452–670 calories/hour at 77 steps/min).

In conclusion, cardio serves as a valuable component in weight loss when consistently paired with strength training and intentional nutrition, focusing on whole, unprocessed foods. It is not the sole solution but an integral part of a comprehensive strategy for success. Beyond weight loss, incorporating heart-pumping activities throughout the week offers broader health benefits, including improved cardiovascular fitness, better cholesterol and blood pressure levels, enhanced cognitive function, and reduced risk of chronic disease, contributing to overall physical and mental well-being.