What is it about mid 30s that leads to a decline in athletic performance???

You obviously have lower than average I.Q. Charles Barkley talks about the errors of arguing with people like you.

I specifically stated decline in maximum heart rate and the decrease in performance which will occur 100m & 200m freestyle swimming and 400m & 800m running. In my post I stated increases in mileage can lead to good performances near age 40 for 10000m to 50K.

Gosh you are stupid.

i was never an elite runner (just a guy that ran a few years in college before getting cut).

but i did spend my 20s/30s in very physically demanding military units (rangers, 82nd )

I felt pretty unstoppable in my 20s. Most of the physical training was NEVER harder than anything I did in track. I never got hurt, I could ruck march 12 miles in one morning, hit the gym in the evening, and still have energy.

I distinctly remember turning 30 and suddenly....it just wasn't the same. I could still perform well physically, but I FELT it.

By 32 I was starting to consider moving to less physical units since I just didnt have the motivation anymore to be so physically focused (like I could still do it, I just didnt like it as much since it hurt more).

By 35 I am content going on walks, stretching, and not really working out that much.

This jives with something I read a long time ago by Dr. Stephen Seiler. The link to the website I read it on does not work but I can post some of it here. It was a long series of articles so I don't think posting a couple paragraphs should constitute any copyright violation. He says exactly what you say in his last sentence: "Ultimately, cardiovascular capacity is reduced however, due to the unavoidable decline in maximal heart rate."

Aging and Cardiovascular Function

World records in endurance sports are not accomplished at age 55. Why? Because one of the unavoidable consequences of aging is a decline in the maximal capacity of the cardiovascular system to pump blood and deliver oxygen while removing metabolic waste products. The components of cardiovascular pump performance are 1) the maximal heart rate that can be achieved. 2) The size and contractility of the heart muscle 3) The compliance (stiffness) of the arterial tree. We will look briefly at what is known about aging effects on each of these variables.

Young children generally have a maximal heart rate approaching 220 beats per minute. This maximal rate falls throughout life. By age 60 maximal heart rate in a group of 100 men will average about 160 beats per minute. This fall in heart rate seems to be a linear process so that maximal heart rate can be estimated by the formula 220- AGE. This is an ESTIMATE, however. If we actually measure the maximal heart rates of those same 100 men during a maximal exercise test we would probably see a range of heart rates between 140 and 180. There is no strong evidence to suggest that training influences the decline in maximal heart rate. This reduction appears to be due to alterations in the cardiac electrical conduction system (SA node and Bundle of His), as well as down regulation of beta-1 receptors, which decreases the heart's sensitivity to catecholamine stimulation.

The research picture regarding age effects om maximal stroke volume is far less clear. This is in part due to the technical challenges involved in making these measurements. Studies showing a decline, an increase, and no change can be found in the literature. It appears that if middle-aged and older adults continue to train intensely, stroke volume is well maintained. Heart size in older athletes has been shown to be similar to that of young athletes, and bigger than their sedentary, same-aged peers. Ultimately, maximal stroke volume appears to decrease due to a 1) decrease in training volume and 2) an increase in peripheral resistance.

The blood pumped out of the heart enters the systemic arterial system. In our youth, this system of arteries is quite flexible or compliant. This is important for the performance of the heart. Compliant vessel walls stretch when blood is pumped through them, lowering the resistance that the heart must overcome to eject it volume of blood each beat. As we age, these vessels lose their elasticity. Consequently, resting blood pressure and blood pressure during exercise slowly increase as we age. Continued training appears to reduce this aging effect, but does not eliminate it. Increased peripheral resistance results in a decrease in maximal blood flow to working muscles. However, at submaximal exercise intensities, the 10-15% decrease in blood flow is compensated for by increased oxygen extraction (a-v O2 difference). This compensation is probably possible due to the increased transit time of the blood through the capillary tree.

In the sedentary population, cardiovascular performance declines progressively with age. However, much of this decline is due to 1) physical inactivity and 2) increased body weight (fat). Maximal oxygen consumption declines about 10% per decade after age 25. However, if body composition is maintained and physical activity levels are kept constant, the decline in VO2max due to aging is only about 5% per decade. Prior to age 50, this decline may even be less, perhaps 1-2% per decade in hard training masters athletes. Ultimately, cardiovascular capacity is reduced however, due to the unavoidable decline in maximal heart rate.

How much did your weight change? I got ten bucks that says it was those 10 pounds of fat that made you feel old, not your 10 years in age.

Given his description, it was more like 30 pounds of fat and not 10.

The answer is yes, I am still going to do that run. Age group glory, baby!

I can't really comment on the physiological reasons for performance declines in your mid 30s, but I can comment on how lifestyle affects it all. I didn't run a lot in my 20s, but I certainly drank a lot, ate garbage, and got terrible quality sleep. I could get into decent shape but felt I was limited to probably 17 min 5k and 36-37 min 10k.

In my late 20s, I had a wake up call with my health and had to clean up my diet and start exercising more. By my early 30s, I started running times I had not run since high school and also set PRs in the longer distances that I didn't really run when I was a teenager. Even in the mile, 3k, and 5k, I started flirting with my high school PRs. A lot of it had to do with finally doing some consistent training again, but I gave myself a chance to flourish by cleaning up my lifestyle. Unfortunately, I lost about 3 years of peak fitness to injuries and Covid times, but it felt like the sky was the limit for a bit there when I started taking it seriously again.

In my mid 30s now and I can get close to those times of my early 30s but it certainly feels like the limits are starting to kick in. Some of my paces/times are a touch slower than a few years ago and they require more effort. Maybe I can set a new PR if I focus my training on a certain distance but it's starting to feel like I've reached my limit. The slow decline seems to have begun.

What can really screw you when you get older is the recovery time from injuries and the amount of little aches and pains that pop up. Feels like I'm always dealing with 1 or 2 nagging injuries and am forced to take some time off right after I've just had a good spell of training. Makes it hard to get in consistent training month after month when you always have to take a little time off for something.

And to answer the OP, changes in lifestyle and increased life responsibilities definitely kick in for people in their 30s. If you don't take care of yourself and don't take time for training, of course you are going to decline and it's harder to get back into it. There are some guys that I occasionally run with and they are constantly in and out with fitness and diet but think they can just roll back into fitness like they used. Guess what, it doesn't work like that and of course you feel like crap because you still treat your body like crap yet expect different results.

First, everyone is subject to decline with age. Now, regarding the Pros vs Regular Joes... I think at some point as a pro you are just "done". Sure they are still faster than 99% of the population, but they only compare themselves to their peers, that top top top percentage. Once they can't compete vs other pros, it's time to move on.

Regular Joes, we definitely have to move on because nobody is paying to see us run, or give us an appearance fee or shoe deal. I know by the time I was in my later 20's I was just not interested in continuing to put in the training, and deal with ridged schedule that distance running calls for. I had been training and racing since I was 13, I wanted to do and think about other things.

I remember in my mid20's I could run my HS times without much effort. I was just so much stronger. I had to work so hard in HS to even run my mediocre times, but at 25 or 26 my HS PRs were now splits in races.

IMO the loss of strength and stiffness in your tendons/muscles plays a bigger role than loss of cardio in late 30s-40s. Lower leg injury risk goes way up, and efficiency goes down. On top of that, the injuries make you afraid to do speed work, so you don't do it as much as you should.

With pros, I think sometimes they're stuck training a certain way that worked at 22, but they can't handle anymore.

Yikes. I actually meant to respond to the OP but didn’t feel like scrolling to the top. I honestly didn’t even read your post. You seem like you have some real issues man if a message board post sets you off like that.

I also find people who reference IQ to be quite sad. It comes across as positively Trumpian these days.

I was talking about professional athletes. I ran better than ever last year myself at age 48; but I started late and I'm not a pro.

Kipchoge and Tom Brady are notable exceptions, but a pro athlete being competitive after the age of 35 is NOT the rule. Most careers end after 30-35. Lots of athletes still have the motivation to continue, but they get injured or they just aren't as good anymore as they used to be.

In your 30s it gets harder to train like you used to. If you can find a way to train the same way, the times shouldn't drop much.

It's declining testosterone - test levels drop about 1 percent per year after age 30.

Testosterone is the golden hormone for a male athlete. It's the catalyst for protein synthesis/lean muscle mass, bodyfat reduction, bone health, repair of tissues, recovery, energy output, hematological status, mental well being, sound sleep, etc.

And wait to you cats get to my age (61). I had a testosterone test last year & my level is about 2/3 of my peak levels back in my late 20s! (no wonder I struggle with my daily workouts. Lol).

I'm hypogonadal struggling to stay healthy & maintain a good quality of life into my old age.

Your explanation is pretty comprehensive. What it underscores - though you don't say it - is that while training helps the only thing which significantly delays this inexorable process in aging athletes is doping.

At medical school they teach that testosterone peaks at age 27-28.

You are overlooking the natural decline through aging.

You are right. Recreational sportsmen/women who take their sport up late are not a valid demonstration of how aging affects top athletes.

In other threads it is being touted as natural that athletes are running prs and world class times in their mid-forties. For some reason, some elites appear exempt from the process of biological aging.