Fitness Myths That Refuse to Die — And What the Evidence Actually Says

Soreness occurs when muscles are exposed to new or significantly increased stress, causing microscopic damage to muscle fibers. As your body adapts, the same workout produces less soreness — not less benefit. Research consistently shows that training adaptations, including strength and endurance gains, continue even when soreness is absent. Chasing pain as a goal can lead to overtraining, injury, and burnout. A productive workout is one that challenges you appropriately, not one that leaves you hobbling for days. For more on the value of recovery, see why skipping rest days often slows your progress.

When your body burns fat for energy, it draws from fat stores throughout the body based on genetics, hormones, and overall energy balance — not from the muscles nearest to the exercise. Abdominal exercises strengthen and develop the core muscles, but they do not preferentially burn the fat overlying them. Multiple well-designed studies, including research published in peer-reviewed exercise science journals, have failed to demonstrate spot reduction. A comprehensive routine that combines resistance training, cardiovascular exercise, and sound nutrition is the evidence-supported approach to body composition change.

The concern about bulking up stems from a misunderstanding of muscle physiology. Testosterone is the primary hormone driving large-scale muscle hypertrophy, and women produce substantially lower amounts than men. Research shows that resistance training in women typically produces meaningful strength gains and improved muscle tone while having modest effects on overall muscle size. Competitive bodybuilders who achieve very high muscle mass do so through years of highly specialized training, often with specific nutritional protocols. For most women, regular strength training is associated with improved bone density, metabolic health, and functional strength — not an unwanted change in appearance. For context on how strength training compares to cardio, see our breakdown of what each exercise type does for your body.

Exercise creates the stimulus for adaptation, but the actual physiological changes — muscle fiber repair, glycogen replenishment, nervous system recovery — occur between sessions. Without adequate rest, the body remains in a breakdown state rather than progressing. Overtraining syndrome, a well-documented condition, is characterized by declining performance, persistent fatigue, disrupted sleep, and increased injury risk. Most exercise guidelines from organizations such as the American College of Sports Medicine recommend incorporating rest or active recovery days into any training program. Training smarter, not just harder, is what sustains long-term progress. The evidence on why skipping rest days backfires goes into greater detail on this point.

Cardiovascular exercise burns calories during the session and supports heart and lung health. Resistance training builds and preserves lean muscle tissue, which raises resting metabolic rate — the number of calories your body uses at rest. Research suggests that combining both forms of exercise produces better outcomes for body composition and metabolic health than either alone. Whether your goal is weight management, functional fitness, or disease prevention, a well-rounded program typically includes both. If you're weighing how to structure your time, our comparison of group fitness and solo training may help you consider your options.