Does Rucking Increase Testosterone?

Some ruckers and fitness experts assert that the combination of load-bearing, and long-duration aerobic activity provides a spike in anabolic hormones like testosterone. But is there any truth to this? Does the scientific evidence support the notion that rucking can naturally boost testosterone production in the body? Let's examine the current research.

What Is Testosterone and Why Does It Matter?

Testosterone is an androgenic hormone produced primarily in the testes of men and the ovaries of women. It plays a crucial role in male physical development and health. In men, testosterone is responsible for:

• Growth of body hair, muscle mass, and bone mass

• Deepening of the voice during puberty

• Sex drive and fertility

• Production of red blood cells

• Mood, cognitive function, and energy levels

Maintaining healthy testosterone levels as men age can help preserve muscle mass, bone density, libido, and overall vitality. Low testosterone is associated with depression, fatigue, reduced sports performance, and erectile dysfunction. So for many men, especially athletes, keeping testosterone production high naturally is a priority. Rucking has been promoted as one way to potentially accomplish that.

What Causes Testosterone Levels to Rise and Fall?

Testosterone production is regulated by the hypothalamic-pituitary-gonadal axis. The hypothalamus and pituitary gland in the brain monitor testosterone levels and signal the testes or ovaries to produce more as needed. Several factors are known to strongly influence testosterone concentrations:

Strength Training

Multiple studies show that compound exercises like squats, deadlifts, and bench presses acutely boost testosterone, especially when lifting close to your 1 rep max. This is likely an evolutionary adaptation to help men perform physically demanding tasks.

High-Intensity Interval Training

All-out sprints and high-intensity intervals lasting 30 seconds to a few minutes markedly increase testosterone. The spikes are short-lived though, returning to baseline within an hour of exercise finishing.

Sleep

Getting at least 7-8 hours per night of quality sleep is vital for optimal testosterone production. Lack of sleep chronically lowers testosterone.

Stress

Physical, emotional, and mental stress all can suppress testosterone levels if sustained over long periods.

Caloric Intake

Consuming adequate calories and nutrients supports healthy testosterone levels. Severe calorie restriction and starvation diets tend to decrease testosterone dramatically.

Body Fat Percentage

Higher adiposity (body fat) is associated with lower testosterone, likely due to aromatization of testosterone to estrogen in fat tissue.

Age

Testosterone declines naturally as men get older. The drops are gradual, about 1% per year after age 30.

Medical Conditions

Certain health conditions like type 2 diabetes, obesity, and hypertension are linked to lower testosterone.

So the question is, can rucking influence testosterone by impacting some of these known factors?

Does Carrying Heavy Weight During Rucking Increase Testosterone?

One of the hypothesized mechanisms by which rucking could increase testosterone is the heavy weight on your back. Lots of weight-bearing exercise boosts testosterone temporarily. But what does the research actually indicate about walking or hiking with a weighted backpack specifically? A 2020 study had healthy young men complete two experimental trials in random order:

• 75-minute treadmill walk with no load

• 75-minute treadmill walk with a 20kg (44lb) backpack

They measured testosterone levels before, immediately after, and 60 minutes post-exercise. Wearing the weighted backpack caused no significant differences in testosterone at any time point compared to unloaded walking. Another experiment had young men perform 90 minutes of treadmill walking carrying either 0%, 20%, or 40% of their body weight. Testosterone remained unchanged across all loading conditions. Based on the current research, it appears that walking or hiking while carrying weights does NOT inherently increase testosterone production.The loads are likely too low compared to very heavy strength training, which can spike testosterone acutely. The longer duration but lower intensity of rucking fails to create the same effect.

Does The Duration of Rucking Boost Testosterone?

Another potential mechanism is that the longer duration of rucking sessions, often 1-4 hours, might cumulatively raise testosterone across the entire workout. Moderate to high-intensity aerobic exercise lasting more than 60 minutes has been shown to increase testosterone versus shorter workouts. The effect is dependent on exercise intensity though. Unfortunately, no studies have specifically investigated hormonal responses to rucking for multiple hours yet. But related research on prolonged walking with weight carriage provides some clues:

• 90 minutes of treadmill walking with 0%, 20%, or 40% body weight had no impact on testosterone.

• 2 hours of hiking while carrying 61lb (27.7kg) increased testosterone minimally, only in the last 30 minutes of exercise.

• 3 hours of loaded marching with 35lb (15.5kg) had no testosterone-boosting effect.

Based on the evidence, rucking duration alone seems unlikely to increase testosterone. The exercise intensity may simply be too low. More research is still needed on longer rucking workouts though.

Do Other Exercise Elements of Rucking Increase Testosterone?

Aside from load carriage and duration, rucking includes other physical stressors that could potentially affect testosterone:

Metabolic Demand

Rucking requires moderately high energy expenditure for long periods, depending on the load and terrain. This metabolic demand may influence testosterone. However walking on an incline treadmill for 90 minutes, which substantially increases energy cost, showed no change in testosterone levels. This suggests metabolic demand alone from rucking is not enough to increase testosterone.

Muscle Damage

The repetitive impact forces of long-distance rucking can cause mild muscle damage, inducing muscle protein breakdown and inflammation. Research shows that muscle-damaging eccentric exercise may amplify acute spikes in testosterone. It's unclear if rucking generates sufficient muscle damage though.There is certainly much less muscle damage from rucking compared to intense eccentric lifting.

Psychological Stress

The mental toughness required to complete long rucking sessions could potentially increase psychological stress. But it's unknown if rucking induces greater mental stress than other endurance sports that have not been shown to increase testosterone like distance running. More research would be needed to determine if these other exercise elements affect testosterone. Currently, there is insufficient evidence.

Should You Ruck to Increase Your Testosterone?

Based on the current scientific literature, rucking does not appear to increase testosterone or alter hormone levels significantly compared to other types of aerobic exercise. The combination of moderate load carriage, long-duration activity, and muscle damage is apparently insufficient to produce major hormonal changes. However, more research is still needed on longer rucking workouts and varying conditions. There may be specific rucking protocols that could potentially influence testosterone. For now, strength training, high-intensity intervals, adequate sleep and nutrition, and stress management seem far more effective for optimizing testosterone than rucking alone. Rucking remains an excellent way to build muscular endurance, cardiovascular fitness, and mental toughness. However, hormonal benefits are not well supported scientifically. It's best to have realistic expectations when adding rucking to your training routine or lifestyle. Rucking has many advantages, but boosted testosterone may not be one of them based on current evidence. As with any fitness endeavor, it's smart to consult your healthcare provider before starting a new exercise program like rucking. Monitor your body and make sure to allow proper rest and recovery between training sessions.