11 Differences Between Swimming and Gym Workouts That Impact Weight Loss

If you want to lose weight, choosing the right exercise matters more than you might think. Swimming feels gentle and full-body, while gym workouts promise measurable progression. Both burn calories, but they influence appetite, muscle, metabolism, and long-term results in different ways. A surprising piece of research deserves to lead this conversation: people who exercise in cool water can feel much hungrier afterward and may eat back a large share of their burned calories (NutritionFacts.org). That finding helps explain why some swimmers report little or no weight loss despite regular pool sessions.

1. Calorie burn: how the numbers actually compare

When most people ask which is better for weight loss, they mean “which burns more calories.” The short answer is: it depends on intensity, body size, and workout type. For a 155-pound person, vigorous lap swimming burns about 360 calories in 30 minutes, which sits close to vigorous rowing at 369 calories and above vigorous stationary cycling at about 278 calories (Harvard Health, cited in Women's Health). Those numbers show that swimming is competitive with many gym cardio options—not magically superior, but solid.