The never-ending debate: strength training vs. endurance training
The topic of fitness and sport has gained enormous importance in recent years. Whether for aesthetic, health-related, or performance-oriented reasons, more and more people are searching for the optimal form of training for them. Two types of training play a particularly central role: strength training and endurance training. Men, in particular, are often interested in the question of which form of training is better suited to achieving their fitness goals. Is it weightlifting or endurance running? And how do these two types of training affect the body, especially with regard to testosterone, the most important male sex hormone?
Testosterone significantly influences muscle mass, fat burning, and overall physical performance. However, the impact of strength and endurance training on testosterone can vary considerably.
In this article, we'll take a closer look at what strength training and endurance training actually are, the different forms they take, and how they affect the male body, particularly testosterone levels. We'll also address the differences between the sexes and examine whether there really is a "better" form of training for men.
What is strength training?
Strength training, also known as resistance training, is a form of exercise in which the body works against external resistance. The goal of strength training is to increase muscle strength and mass. Resistance can be provided by dumbbells, machines, body weight, or other training equipment. There are various forms of strength training, each with different goals and targeting different muscle groups.
• Free weight training: This includes lifting dumbbells, barbells, or kettlebells. It requires stability and body control.
• Machine training: This involves using machines that restrict the range of motion, thus targeting the training effect specifically to certain muscles.
• Bodyweight training: This uses your own body weight to create resistance. Push-ups, squats, and pull-ups are classic exercises of this type.
• Functional training: This type of training aims to imitate everyday movements and improve the body's functionality. This can be done with or without additional weight.
Strength training is particularly interesting for men because it not only increases muscle mass but can also positively influence testosterone levels. Studies have shown that intensive strength training, especially with heavy weights and complex movements, leads to an increase in testosterone levels ( Craig et al., 1989 ). But strength training doesn't just affect testosterone. It strengthens the cardiovascular system, promotes bone density, and has positive effects on metabolism ( Miko et al., 2020 ).
What is endurance training?
Endurance training, also known as cardiovascular training, encompasses all types of exercise aimed at increasing the body's endurance. It promotes the efficiency of the cardiovascular system and improves the ability to perform physical exertion for extended periods. Typical forms of endurance training include:
• Running: Jogging and running are among the classic endurance exercises that can be performed both outdoors and on a treadmill.
• Cycling: Whether on a stationary bike or on a bike tour, cycling is a joint-friendly method to build endurance.
• Swimming: Swimming offers a full body workout and is particularly gentle on the joints.
• Rowing: Rowing on a rowing machine or in the water not only trains endurance, but also the back muscles.
• HIIT (High Intensity Interval Training): This form of training combines high-intensity exertion phases with short rest periods and is becoming increasingly popular to promote both endurance and strength.
Unlike strength training, endurance training is not primarily aimed at building muscle mass. Instead, the focus is on improving aerobic capacity and fat burning. However, research also shows that endurance training has positive effects on health, strengthens the cardiovascular system, and can reduce stress ( Marmat et al., 2020 ).
Advantages and disadvantages of strength and endurance training
Benefits of strength training
1. Muscle building
Strength training is the most effective method for building muscle mass because it provides targeted stimuli that encourage muscle fiber growth. More muscle mass means a higher basal metabolic rate, even at rest, since muscles burn more calories than fat. This is beneficial not only for physique but also for long-term weight management and overall health ( Beneke R., 1998 ).
2. Strengthening the skeletal system
Regular strength training increases bone density because the mechanical stress stimulates bone formation. Strength training has a particularly preventative effect in old age, when the risk of osteoporosis increases. Studies show that even older people can improve their bone strength and thus their mobility through moderate strength training ( O'Bryan et al., 2022 ).
3. Testosterone increase
Intense strength training, especially with heavy weights and low repetitions, leads to a short-term increase in testosterone levels. ( Craig et al., 1989 ) . Testosterone is crucial for muscle growth, recovery, and overall vitality. A consistently higher level promotes physical performance and reduces age-related decline (Harvard Health, 2023) .
4. Improved posture and functionality
Functional strength training not only strengthens muscles but also improves body stability and balance ( Xiao et al., 2023 ). This leads to better posture and reduces the risk of back problems. Exercises like deadlifts and planks train multiple muscle groups simultaneously, which has a positive impact on everyday movements.
Disadvantages of strength training
1. Increased risk of injury
Poor technique or excessively heavy weights can lead to injuries such as muscle strains or joint problems. Without professional instruction or a proper warm-up, this risk increases significantly. Beginners, in particular, often underestimate the importance of correct form.
2. Higher demands on technology and equipment
Effective strength training requires a certain level of technical know-how to perform exercises correctly and target specific muscle groups. Furthermore, equipment such as dumbbells, machines, or even a gym membership is often necessary, which can represent an investment of time and money.
Benefits of endurance training
1. Improvement of cardiovascular health
Regular endurance training strengthens the heart, improves blood circulation, and lowers blood pressure. This significantly reduces the risk of cardiovascular diseases such as heart attack or stroke. ( Marmat et al., 2020 ) A stronger heart works more efficiently, which is also noticeable in everyday life, e.g. through more energy and less fatigue.
2. Increased stamina
Endurance training improves the body's ability to efficiently supply energy over extended periods. This increases overall performance, whether in sports, at work, or in everyday life ( Morat et al., 2017 ). Those who regularly engage in endurance training often notice that climbing stairs, taking long walks, or performing physically demanding tasks become significantly easier.
3. Stress reduction
Endurance training leads to the release of endorphins, the so-called "happiness hormones." This helps reduce stress, improve mood, and promote mental health. Studies have shown that people who regularly run, cycle, or swim are less susceptible to depression and anxiety disorders ( da Costa et al., 2022 ).
4. Fat burning
During endurance training, the body draws on stored fat reserves, especially at moderate intensities. This makes it an excellent method for weight management. Furthermore, it improves insulin sensitivity, which boosts metabolism in the long term and reduces the risk of type 2 diabetes ( Orlando et al., 2016 ).
Disadvantages of endurance training
1. Muscle loss due to overtraining
With excessively intense or prolonged endurance training, the body can begin to use muscle mass as an energy source. This is because the elevated cortisol, a stress hormone, promotes catabolic processes. In the long run, this can lead to a leaner but less muscular physique, which is undesirable for many men.
2. Stress on the joints and overuse injuries
Especially in sports like running or intensive cycling, joints, tendons, and muscles can be overloaded. Without sufficient recovery, overuse injuries such as shin splints, Achilles tendonitis, or knee problems can develop. A varied training routine and proper technique are essential here.
This detailed explanation makes the advantages and disadvantages not only easier to understand, but also more thoroughly presented.
Differences between men and women
Although the benefits and drawbacks of strength and endurance training are largely the same, there are differences between men and women regarding the body's response to these forms of exercise. Men generally have more potential to build muscle mass due to their higher testosterone levels, while women tend to respond better to endurance training because their physical makeup allows for greater fat burning.
However, this does not mean that men cannot benefit from endurance training, or that women cannot make progress in strength training. Everyone, regardless of gender, can benefit from combining both forms of training.
The connection with testosterone
How testosterone affects the body
Testosterone is the primary male sex hormone and plays a central role in many physiological processes ( Roney & Gettler, 2015 ). It is particularly important for the development and maintenance of muscle mass. High testosterone levels are associated with reduced body fat percentage and improved fat utilization ( Kelly & Jones, 2015 ). Testosterone also influences mood and energy levels, which is why men with higher testosterone levels are often perceived as more motivated and energetic.
During resistance training, the body is subjected to high stress, which strains the muscle fibers and creates micro-tears. This process initiates a healing and adaptation process in which the body repairs the damaged muscle fibers and restores them to a stronger state. The hormonal increase in testosterone supports this process by promoting muscle growth and accelerating regeneration. Studies show that both intense resistance training and periods of maximal exertion (e.g., sets with few repetitions and heavy weights) stimulate testosterone production ( Kvorning et al., 2006 ).
How testosterone levels affect training performance
It's no secret that higher testosterone levels lead to better training performance. Men with higher testosterone levels can generally lift heavier weights, recover faster, and have overall greater performance in strength training. Conversely, a testosterone deficiency can lead to muscle loss, reduced energy, and poorer performance.
Numerous scientific studies have shown that testosterone levels influence the ability to cope with intense training loads. Men with higher testosterone levels are able to perform more intense strength exercises, leading to better muscle adaptation to the load and faster muscle growth ( Bhasin et al., 1996, Kraemer et al., 2004 ).
Another interesting aspect is that testosterone plays a role not only during training but also in the recovery phase after a workout. Studies show that testosterone has a direct influence on protein synthesis, which is crucial for muscle growth. A sufficient increase in testosterone levels after training helps to efficiently repair and build muscle ( Howard et al., 2022 ).
The influence of strength training on testosterone
Testosterone plays a crucial role in a man's body. It influences not only the development of male sexual characteristics but also muscle development, fat distribution, and overall vitality. Testosterone levels vary throughout a man's life, generally declining with age. But how exactly does strength training affect testosterone levels?
Several studies have shown that intensive resistance training can significantly increase testosterone levels. Particularly with heavy weights and short, intense sets (e.g., 3-6 repetitions), a post-workout increase in testosterone has been observed ( Kraemer et al., 1999 ). It is assumed that the body attempts to recover from the exertion and promote muscle growth in this way, which is associated with an increase in testosterone.
However, the increase in testosterone after strength training is only temporary and can decrease again after a certain period. The long-term effects on testosterone levels depend on the frequency and intensity of the training. However, consistent strength training can lead to a stabilization or even an increase in testosterone levels over time.
The influence of endurance training on testosterone
Unlike strength training, endurance training has a rather ambivalent effect on testosterone levels. While moderate endurance training such as running or cycling may slightly raise testosterone levels, excessive endurance training, especially in the form of long, intense workouts, can lead to a decrease in testosterone.
Studies, such as that by Hackney et al. (1988) , have shown that endurance athletes tend to have lower testosterone levels than strength athletes. This could be due to the high stress placed on the body during prolonged endurance training, which leads to an increase in cortisol, a stress hormone that can negatively affect testosterone levels.
The role of cortisol in endurance training
A key factor in why excessive endurance training can negatively affect testosterone levels is the hormone cortisol . Cortisol is known as the stress hormone and is produced by the body during periods of high exertion or stress. Endurance sessions that are too long or too intense increase cortisol levels, which in turn can negatively impact testosterone levels. This connection was demonstrated in a study by Maimoun et al. (2003) .
While moderate endurance training such as easy running or cycling does not significantly increase cortisol levels, intensive training, as is common among marathon runners or elite athletes, can lead to chronically elevated cortisol levels. Elevated cortisol levels over extended periods can suppress testosterone levels, which can have long-term negative effects on muscle mass and fat metabolism.
Endurance training and fat burning
However, one positive effect of endurance training is the increased ability of the body to burn fat. It is generally accepted that endurance training promotes fat burning because the body relies on fat as an energy source for a longer period. This could also be beneficial with regard to testosterone, as a lower body fat percentage is associated with higher testosterone levels. Studies show that men with lower body fat percentages tend to have higher testosterone levels ( Ma et al., 2024 ).
The question of whether endurance training or strength training leads to higher testosterone levels in the long term is complex and depends on many individual factors. It could even be argued that a combination of both – moderate endurance training for fat burning and strength training to increase muscle mass and testosterone – yields the best results.
How strength training and endurance training can work together
Many men who want to improve both their endurance and muscle mass wonder if it's possible to train both at the same time. In fact, recent scientific studies show that combining strength and endurance training is indeed possible and beneficial, as long as certain basic principles are followed.
Timing and sequence of training sessions
There are various approaches to combining strength and endurance training. One of the most important considerations is the order of the training sessions. A commonly recommended strategy is to perform strength training before endurance training . This is because intense endurance sessions can fatigue the muscles, which impairs performance in the subsequent strength training. Therefore, if you want to train both endurance and strength in one session, it makes sense to start with strength training when your energy levels are at their highest.
Periodization and variation
Another way to effectively combine strength and endurance training is through periodization . This involves alternating phases of intensive strength training with phases of intensive endurance training. This method has proven particularly effective in increasing muscle mass and improving endurance without neglecting either goal. Such a training plan ensures variety and prevents the body from adapting to a single training stimulus, leading to better long-term results.
Combining training methods for greater success
For many men who want to build strength and improve their endurance, a combination of both training types is often the best approach. Studies have shown that men who perform a mix of strength and endurance training achieve better overall results in terms of body composition, muscle retention, and general fitness.
A good training plan could look something like this:
• Monday: Strength training (legs and back)
• Tuesday: Endurance training (light running or cycling)
• Wednesday: Strength training (upper body and arms)
• Thursday: Active recovery (light endurance activities such as swimming or yoga)
• Friday: Combination of strength and endurance training (interval training or circuit training)
Differences in the effects of strength and endurance training in men and women
Although both men and women benefit from strength and endurance training, there are gender-specific differences worth considering. The influence of testosterone on muscle growth and fat burning plays a particularly important role here.
Male physiology: Higher testosterone levels and muscle growth
Men generally have significantly higher testosterone levels than women, which helps them make faster progress in muscle building and strength training. This higher testosterone not only promotes muscle growth but also contributes to fat burning. Men can build muscle mass more quickly with strength training and often have a higher basal metabolic rate, giving them an advantage when it comes to fat burning.
Female physiology: Lower testosterone and a different training response
Women have significantly lower testosterone levels compared to men, which means they generally build less muscle mass ( Ikehata et al., 2023 ). However, this does not mean that women cannot be successful in strength training—they simply have a different physiological response to it. Women can increase their muscle strength and reduce their body fat percentage through strength training, but the muscle gains are usually not as pronounced as in men.
Women generally respond better to endurance training, especially when it comes to improving aerobic capacity and burning fat. Female endurance athletes tend to have lower body fat percentages and can particularly benefit from moderate endurance training.
Case study: How Jonas found the right training strategy for his body
Jonas is 36 years old, works as an IT project manager, and leads a generally active life. For years, he made sure to get enough exercise, primarily through regular running sessions. He jogged two to three times a week after work, also participated in half marathons, and was proud of his athletic endurance.
Despite this, Jonas felt like he was physically stagnating. His energy levels fluctuated, his physique was barely defined, and even after extended cardio sessions, his weight and body fat percentage hardly changed. He also noticed a gradual decline in his motivation to train, his libido, and his sex drive. Initially, he attributed it to work stress, but eventually, he realized there had to be more to it.
A comprehensive medical check-up revealed that his testosterone level, at 11.8 nanomoles per liter, was below the age-appropriate average. The doctor diagnosed functional testosterone deficiency. While the level wasn't clinically critical, it showed clear symptoms – typical for men who do a lot of endurance training but provide little muscular stimulation.
The training paradigm shift through combination instead of one-sidedness.
After a detailed consultation, Jonas decided to begin a personalized testosterone replacement therapy, accompanied by regular monitoring. At the same time, his training plan was revamped. His focus shifted from pure endurance training to a well-planned combination with strength training to more effectively support and sustainably increase his hormone production.
Twice a week he now completed intensive strength training with basic exercises such as squats, deadlifts, and bench presses. He also incorporated circuit training to improve his muscular endurance. Long runs were replaced by one or two moderate cardio sessions per week. His new training program was structured, varied, and designed to support his hormonal balance.
His daily routine also changed. Jonas paid closer attention to his diet: more protein, healthy fats, fiber-rich foods, and natural sources of important micronutrients like vitamin D, zinc, and magnesium. This type of diet can have a positive effect on testosterone production. He cut out sugar, alcohol, and highly processed foods, which improved not only his hormone levels but also his overall fitness.
His sleep became a priority. Jonas managed to stabilize his sleep rhythm and get at least seven hours of sleep per night. Less screen time in the evening, relaxation exercises, and a structured daily routine meant he woke up feeling more refreshed—an important factor in naturally increasing his testosterone levels.
Stress management was another key aspect. Chronic stress raises cortisol levels, which inhibits testosterone production. Through conscious breathing, regular breaks, and physical activity in his daily routine, Jonas managed to significantly lower his stress levels. This allowed him to actively improve another factor influencing his hormone levels.
The result after three months
Jonas's body began to visibly change. He gained more muscle, reduced body fat, and developed a more defined physique. He felt more powerful, mentally more stable, and sexually active. His libido returned, his self-confidence increased, and his training showed a significant improvement in performance.
A follow-up blood test confirmed the subjective impression: his testosterone level was now stable in the upper normal range. His hormonal balance had improved – both through medical support and lifestyle factors such as targeted training, a conscious diet, restful sleep, and reduced stress. His overall fitness benefited from this holistic approach.
“I never would have thought that too much endurance training could have harmed my hormone balance. Only the combination of strength training, therapy, and a conscious diet flipped the switch for me. And the best part: I feel like myself again.”
Why Jonas' path is groundbreaking for many men
Jonas is not an isolated case. Many men over 30 or 40 focus solely on endurance training to burn fat and stay healthy, neglecting the crucial role of testosterone, muscle stimulation, and hormonal balance. Low testosterone levels not only affect muscle growth but also energy levels, mood, sleep, libido, and sexual performance.
A balanced strength training program, combined with targeted nutrition, proper recovery, and appropriate medical support, can increase the production of this important hormone—effectively and sustainably. Those who recognize the signs early can not only optimize their testosterone levels through targeted measures but also significantly improve their overall quality of life.
Regular monitoring of free testosterone, not just total testosterone, is also essential. This is the only way to determine how much biologically active hormone is actually available to the body.
Tips for men who want to naturally increase their testosterone production
Many of these steps can easily be integrated into everyday life:
- Combine targeted strength training with moderate endurance training.
- Make sure you get restful sleep, at least seven to eight hours a day.
- Actively reduce stress to keep cortisol levels low.
- Eat a nutrient-rich diet: zinc, magnesium, vitamin D, omega-3 fatty acids
- Maintain a healthy body weight; being overweight lowers testosterone levels.
- Avoid nicotine and excessive alcohol consumption.
- Maintain regular exercise, sex, and conscious relaxation
In conclusion: Those who take their hormonal health seriously are investing not only in muscle mass or appearance, but also in joie de vivre, vitality, libido, sleep quality, and long-term fitness. Hormonal balance is crucial for how we feel in our own bodies—physically, sexually, and mentally. Men who learn to listen to their bodies' signals and act accordingly improve their well-being sustainably and naturally.
Conclusion: Strength training and endurance training are the optimal combination for men
The question of which type of training is better for men – strength training or endurance training – cannot be answered definitively. Both types of training have their specific advantages and complement each other when combined in a balanced training plan.
For men who want to build muscle mass and optimize their testosterone levels, strength training is key. Those who also want to improve endurance or reduce body fat should incorporate cardio training into their plan. The combination of both offers the best results and ensures a holistic improvement in physical fitness.
Testosterone plays a key role: strength training promotes an increase in testosterone, while endurance training can help reduce body fat, which also leads to higher testosterone levels. Finding the right balance and individual training approach is crucial for long-term success.
