Cardio Timing: Before or After Workouts for Optimal Results

What is the Difference Between Doing Cardio Before or After a Workout?

The optimal timing for cardio relative to resistance training is a nuanced decision, primarily dictated by individual fitness goals, as prioritizing one form of exercise can impact the performance and physiological adaptations of the other.

Understanding the Physiological Impact

The human body relies on different energy systems depending on the type, intensity, and duration of activity. Resistance training primarily uses the phosphagen system and anaerobic glycolysis for short, intense bursts, while moderate-to-high intensity cardio relies heavily on aerobic metabolism. The order in which these activities are performed can influence substrate utilization, central nervous system fatigue, and specific training adaptations.

Cardio Before Resistance Training: The "Pre-Exhaustion" or "Warm-Up" Approach

Performing cardio before lifting weights is a common practice, but its effectiveness depends heavily on the cardio's intensity and duration.

• Benefits:
  • Enhanced Warm-up: A light, low-intensity cardio session (5-10 minutes) effectively raises core body temperature, increases blood flow to muscles, and prepares joints for movement, reducing the risk of injury during subsequent resistance training.
  • Improved Cardiovascular Readiness: For individuals whose primary goal is cardiovascular health, a more substantial cardio session beforehand ensures it's completed with fresh energy.
• Considerations and Potential Drawbacks:
  • Fatigue and Performance Impairment: Engaging in moderate to high-intensity cardio before resistance training can deplete muscle glycogen stores and induce central nervous system fatigue. This pre-fatigue can significantly impair strength, power, and overall lifting volume during the resistance training session, potentially compromising strength gains and muscle hypertrophy.
  • Reduced Quality of Lifting: With pre-fatigued muscles, maintaining proper form during resistance exercises becomes more challenging, increasing the risk of injury and reducing the effectiveness of the strength stimulus.

Cardio After Resistance Training: The "Finisher" Approach

Placing cardio after resistance training is often recommended for those prioritizing strength, power, or muscle growth.

• Benefits:
  • Maximized Strength Performance: By performing resistance training first, muscles are fresh, glycogen stores are full, and the central nervous system is un-fatigued, allowing for maximal effort, heavier loads, and higher quality repetitions. This optimizes the stimulus for strength gains and muscle hypertrophy.
  • Potential for Enhanced Fat Oxidation: After a resistance training session, muscle glycogen stores are partially depleted. Performing cardio immediately afterward can lead to a greater reliance on fat as a fuel source, potentially enhancing fat oxidation during the cardio session.
  • Metabolic Boost: Both resistance training and cardio contribute to an elevated post-exercise oxygen consumption (EPOC), or "afterburn," which increases calorie expenditure even after the workout.
• Considerations and Potential Drawbacks:
  • Fatigue for Cardio: The fatigue accumulated from resistance training might reduce the intensity or duration you can sustain during your cardio session, potentially impacting cardiovascular adaptations if high-intensity cardio is the goal.
  • Risk of Overtraining: Combining intense resistance training with intense cardio in the same session, especially without adequate recovery, can increase the risk of overtraining and burnout.

Impact on Specific Fitness Goals

The "before or after" dilemma largely hinges on your primary fitness objective.

• For Strength and Hypertrophy (Muscle Growth):
  • Recommendation: Prioritize resistance training. Performing cardio after lifting, or ideally, on separate days, allows you to maximize your strength and power output during your lifts, which is crucial for progressive overload and muscle development. If cardio must be done before, keep it very light and brief (5-10 minutes).
• For Endurance and Cardiovascular Health:
  • Recommendation: If endurance is your primary goal, performing cardio before resistance training, or on separate days, allows you to dedicate your freshest energy to improving cardiovascular fitness. However, be mindful of the potential impact on subsequent resistance training if performed in the same session.
• For Fat Loss:
  • Recommendation: While the timing can have minor metabolic nuances, the most critical factor for fat loss is total caloric deficit, which comes from overall energy expenditure and dietary control. Both orders can be effective. Performing cardio after weights might slightly favor fat oxidation, but the difference is often negligible compared to total calories burned. Consistency and total weekly volume are far more important than exact timing within a single session.
• Concurrent Training (Combining Both):
  • Research on the "interference effect" suggests that combining resistance and endurance training can sometimes blunt adaptations in either domain, particularly if both are high intensity and performed too closely together.
  • Mitigation Strategies:
    • Separate Sessions: The ideal scenario for maximizing adaptations in both strength and endurance is to perform them on separate days or with a significant time gap (e.g., 6+ hours) between sessions on the same day.
    • Prioritize Goal: If you must combine them, prioritize the training modality that aligns with your main goal.
    • Vary Intensity: If doing cardio before, keep it low-intensity. If doing it after, adjust intensity based on your fatigue level.

Practical Considerations and Recommendations

• Warm-up vs. Workout: A brief, low-intensity cardio warm-up is always beneficial before resistance training, regardless of your goal. This is distinct from a full cardio workout.
• Listen to Your Body: Pay attention to how your body responds to different timings. If you feel excessively fatigued or your performance declines significantly in one area, adjust your approach.
• Time Constraints: If you have limited time, doing both in one session is often more practical than skipping one. In such cases, prioritize the exercise type that aligns most with your current goals.
• Enjoyment and Adherence: The best workout schedule is one you can consistently adhere to. If you prefer one order over another and it doesn't significantly derail your goals, stick with it.

Conclusion

There is no universally "correct" answer to whether cardio should be done before or after a workout. The optimal sequencing is highly individualized and depends on your specific fitness goals, current fitness level, and how your body responds to different training stimuli. For those prioritizing strength and muscle gain, performing resistance training first is generally advisable. For endurance-focused individuals, prioritizing cardio may be more beneficial. Ultimately, consistency in training and proper recovery are paramount for achieving any fitness objective.