Combining cardiovascular exercise and strength training on the same day is known as concurrent training. This approach allows individuals to improve both muscle strength and cardiovascular fitness within the same training period. While effective for general health, maximizing the benefits of both simultaneously requires careful planning. Concurrent training relies on understanding how the body adapts to each stimulus and structuring workouts to minimize potential conflict.
The Physiological Conflict Between Training Modalities
The challenge of combining strength and endurance training arises from the body’s cellular signaling pathways, which are activated differently by each exercise type. Resistance training stimulates the mammalian target of rapamycin (mTOR) pathway, initiating muscle protein synthesis, muscle growth, and strength gains. Endurance training activates the adenosine monophosphate-activated protein kinase (AMPK) pathway. AMPK is a cellular energy sensor that promotes adaptations like mitochondrial biogenesis, improving energy efficiency and cardiovascular fitness.
This difference in signaling can lead to the “interference effect” in concurrent training. The AMPK pathway, dominant after endurance exercise, is thought to suppress the mTOR pathway responsible for muscle building. Performing high-volume or high-intensity cardio too closely to a strength session may blunt the anabolic signaling necessary for maximal muscle hypertrophy and strength gains.
This conflict is most pronounced when both training types are high in intensity and volume and performed immediately after one another. The resulting fatigue from the first workout also impacts the quality of the second session. Managing the timing and intensity of the two sessions is the primary strategy for minimizing this physiological trade-off.
Determining Workout Order Based on Primary Goal
The most effective way to structure concurrent training is to prioritize the workout that aligns with your main fitness objective. The order of the two sessions significantly influences the adaptations you experience. Matching the exercise order to your goal ensures you are freshest for the session that matters most to your progress.
If your aim is to maximize strength or muscle growth, perform strength training first. Resistance exercise requires high levels of neuromuscular force, and pre-fatiguing the muscles with cardio compromises lifting technique and reduces the volume you can handle. Follow strength work with moderate-intensity or low-impact cardio, such as cycling, to maintain cardiovascular fitness without interfering with muscle adaptations.
Conversely, if your primary focus is improving endurance, such as training for a race, the cardio session should be performed first. Starting with endurance training ensures you can maintain the necessary pace and duration without residual muscle fatigue from heavy lifting. The subsequent strength training session should focus on maintenance or muscular endurance, rather than maximal strength.
Optimizing Intensity and Timing for Combined Sessions
The most effective way to minimize the interference effect and optimize performance is to introduce a time separation between the two workouts. Experts recommend a minimum time gap of four to six hours between a strength session and an endurance session performed on the same day. This separation allows cellular signaling responses to subside and provides a window for partial recovery and energy replenishment.
For those who must combine both modalities into a single session, focus on intensity management. Avoid pairing two high-intensity workouts, such as maximal strength training followed immediately by high-intensity interval training (HIIT). Instead, pair a high-intensity session with a moderate or low-intensity one, such as heavy lifting followed by a Zone 2 cardio session, which involves a sustained, comfortable pace.
Strategic nutrition is an important component of sustaining the demands of dual training. After the first workout, consuming a recovery snack containing both carbohydrates and protein is advisable, especially if the second session is within a few hours. This combination helps rapidly replenish depleted glycogen stores and delivers amino acids to promote repair. Aiming for 20 to 40 grams of protein and sufficient carbohydrates immediately following a strenuous session supports adaptation to both strength and cardio demands.