It is obvious that there are physical differences between men and women. Men are typically taller, more muscular, and therefore usually outperform women when it comes to upper body performances (like lifting), strength, and power events. This is also true when it comes to shorter-distance events; historically, men outperform women. That being said, this is when it comes to the “average” male and female. Of course, there are outliers, as there are with any comparison. There are some women who will outperform men in their respective events throughout time. There is also the argument of ultradistance competitions, where we see women beating men in longer distance endurance events. All aside, across the board, the needle sways in favor of men outperforming women.
The question is: why?
Is this all to say that the physical differences account for this? Truth be told, the physical differences are what lead to the physiological differences. How do these physiological differences change as we age? Do we maintain our fitness, or do we lose our fitness?
Let’s take a look at what’s under the hood and see for ourselves how these differences either stay the same or change as we get older.
Male and Female Physical Differences
- Heart size
- Transport organs
- Hemoglobin concentration
- Muscle mass
- Percent of fat-free mass
What do these physical differences mean in regard to physiological differences?
A difference for the same absolute submaximal workload. For the same cardiac output, men have a larger heart size and therefore can push more blood per minute to be moved through the cardiovascular system at a higher rate. What does that even mean?! This means an increased oxygen consumption, which directly impacts an individual’s, VO2 Max. When we combine having a greater ventricular ejection volume with higher levels of hemoglobin concentration, this yields a greater cardiac output and again an increased VO2 output. More O2 available = more work that can be done by the aerobic system.
Women on the other hand have a smaller heart size and therefore a decreased ventricular ejection volume. These changes therefore will directly correlate with a decrease in stroke volume and the ability to push less blood per minute. With a smaller physical heart size and less hemoglobin circulating throughout the body; this lower cardiac output seen in women will reduce their VO2 max. The amount of oxygen that can be utilized and the amount of work that can be produced at your VO2 will be reduced.
Bottom line: women have reduced oxygen consumption as compared to their male counterparts on average.
Men have a significant difference in circulating testosterone levels. These androgens (sex hormones) not only allow for greater production of muscle mass but can allow for greater hemoglobin mass and hemoglobin concentration. Male androgens also have an impact on the amount of Erythropoietin (EPO) secreted, to help increase the number of red blood cells that are produced. The more oxygen that is carried in the blood, allows men to carry a greater hematocrit volume. Hematocrit is the volume percentage of red blood cells in the body, and red blood cells are what help transport oxygen throughout.
While men have increased testosterone levels, women have increased estrogen levels. Increased estrogen levels lead to a higher fat mass and lower total body mass.
While potentially a lesser-known difference between men and women – peak lactate concentrations are lower in women compared to men. That being said, the lactate threshold occurs at the same percentage of VO2 max in both males and females. What does this mean exactly? If we think about the percentage of VO2 as someone’s FTP (functional threshold power), then the percentage of FTP at a male/female VO2 max would be the same, but the associated power would be lower in women.
Now that we have discussed the general physical and physiological differences between men and women, let’s take a look at what happens as we begin to…..age.
The Aging Athlete
As we begin to age, even beginning in our mid 30’s to early 40’s we begin to see:
- Reduction in height
- Loss of bone mass
- Body composition changes
- Fat-free mass decreases
- Hormone decrease
Reduction in height is linked to compression of our intervertebral discs and loss of bone mass – known as osteopenia/osteoporosis. We also begin to see a loss in our total body mass which comes from a loss of muscle mass (also known as sarcopenia). The reduction in muscle mass can be linked to a decrease in our appetite as well as an overall decrease in our workout levels.
When it comes to hormones, we see a decrease in one specific: LGF1 – Insulin-Like Growth Factor 1. This hormone manages the amount of growth hormone (GH) that circulates in your body. This hormone is important since it promotes the growth of bones and tissues throughout the body. In addition to a decrease in LGF1, we begin to see a decrease in testosterone.
What can we do?
It may be easy to sit back and say that these changes are inevitable, it is up to us to do something about what we can control. This includes our diet, endurance training, and resistance training. Diet makes a huge impact on our body composition: this includes our fat-free mass and our percentage of body fat. How you can manage your nutrition around how your body still responds to training can help to promote higher production of growth hormones. This means making sure you’re getting in carbohydrates and proteins immediately post-exercise to replenish the empty stores.
While endurance training is great for continued overall cardiovascular health, it has little effect on our decrease in muscle mass as we age. Resistance training is vital as we get older. Whether you have a long history of strength training or never picked up a weight in your life, it is never too late to get started. Strength training helps us to maintain our strength and bone density. Maintaining our bone density adds to our fat-free mass stores and can help to decrease negative changes in total body mass.
Age and Impacts on Oxygen Consumption
What can we expect to see over time?
- Decrease in max heart rate over time
- 10% decrease in O2 consumption per decade
Between the ages of 25-35 years, we begin to see a 1% decrease per year in our overall oxygen consumption. Studies have shown that there is a bit of reduction in decline when there is a greater amount of training incorporated. What this means is don’t neglect higher intensity intervals in training. Having intensity helps to influence our overall aerobic capacity. We don’t need to perform intervals daily, but try to incorporate them 1-2 times per week. What we will need to consider when performing intensity as we age is that our rate of recovery is slower. While at one point we may have been able to perform high-intensity work on back-to-back days, we may need an additional few days in between to ensure proper recovery.
The Research and Silver Lining
While it may seem like women have drawn the short straw when it comes to performance in sports…there is a silver lining. Wahoo Sports Science (WSS) has (and still is) performed one of the largest studies comparing men’s and women’s performances in cycling. WSS has collected data from over 7,000 individuals: equally split between female and male test subjects who performed Power Profiling*. Not only does this data show male and female differences, but it also was able to look at 5 different age groups separated by a decade: 20, 30, 40, 50, and 60-year-olds. The Sports Science team looked at the impact of age and gender on the changes in sprint power, anaerobic power, VO2Max (MAP) power, and threshold power.
*performing the Full Frontal test: 2×5 second full sprints, 5-minute maximal effort, 20-minute maximal effort, and a final 1-minute maximal effort all off of 5 minutes rest between.
- There is a difference in sex across all 4 categories of intensities. Men all produced higher power than women in each age category.
- There is a difference in changes of power between age groups. Both men and women saw decreases in all power intensities as age increased.
- Women have a slower rate of decline in aerobic power values as compared to men.
Therefore: women maintain aerobic power better than their male counterparts.
There is no sugarcoating it, with age comes an eventual decrease in our performance. What is important to understand is that we can influence this decline! The saying goes, “use it or lose it.” By continuing to train with high-intensity intervals, resistance training, and maintaining proper nutrition, we can keep the decline at bay. Don’t let “age” keep you from doing the things you love or believing your best days are behind you, there are still plenty of PRs to chase on the horizon!