How To Protect & Improve Your Fertility As A Man - Dr Michael Eisenberg - #969

**Chris Williamson** (0:00)
Global sperm counts have declined by over 50 percent in the last 40 years. Is that true?

**Dr. Michael Eisenberg** (0:08)
You know, it really is. I think, you know, in the last few years, there's been a lot of consensus around that. You know, one of the most famous studies that looked at this was published in the 90s. And, you know, when it was released, I've talked to some of the authors about it, there was a lot of fainter around it. You know, they had it in a big media hall, there were television cameras. But since then, there was a lot of controversy around it. You know, for a few reasons, you know, there are differences in semen quality around the world. Like, for example, there was a study in the United States that showed, if you can believe it, sperm quality is higher in New York than in the Midwest. And I think reasons for that are not certain. You know, whether it's lifestyle, you know, activity levels, there may be differences in, you know, just sort of race, ethnicity composition. I think the reasons are not known. But, you know, in the US, we see that. But around the world, we see that too. And so there were some concerns about how well that was incorporated to some of these studies. You can imagine over 40 years, some of the methodology for testing sperm has probably improved a little bit. Even our, you know, statistical methodologies, compute computational abilities have improved. So, you know, initially in the 90s, I think it was somewhat controversial. Even some of my mentors question this. But I would say over the last, you know, few years, there was another study in 2017, then even 2023 most recently. And it's really kind of solidified. And now there's consensus in the field that we're seeing this decline over the last 50 years. Maybe it's called about 1%, so maybe about 1 million less sperm per year on average every year. But over the last 10, 20 years, it's accelerated actually about 2% decline. And so I think it's, you know, now that there's a little more, again, sort of consensus around it, I think it's really up to us to understand why. Because, yeah, it's not a good thing. Existential, I think, in a lot of ways.

**Chris Williamson** (1:50)
Okay, why do we think that this is happening? Beyond the ability to detect statistical improvements physically, what's happening?

**Dr. Michael Eisenberg** (1:59)
Yeah, I mean, I think that's the million dollar question, or billion, or trillion dollar question, really. I think there could be a few reasons. You know, the pace of change is probably too quick for evolution. I don't think it's a genetic factor. You know, so I think people have really honed in on exposures. You know, whether it's, you know, lifestyle factors. I mean, I think that, you know, we're probably a little less sedentary than we used to be. You know, obesity was going up, although maybe with some of the new medications, we'll see a reversal of that trend. But I think there's a lot of concern about just some of our exposures. You know, some of the chemicals in the environment, microplastics, I think those sorts of things. You know, there's some endocrine disrupting factors that are at play here that may be the culprits. But I think, you know, we need to really do more work to try and understand it. And I think that's kind of where we are.

**Chris Williamson** (2:42)
So you, at the forefront of this, have a broad perspective that stuff's not great, numbers are going in the wrong direction. We kind of have an idea of what's going on, but actually finding an individual target or a couple of targets that we could intervene with, it sounds like a pretty complex problem to try and solve.

**Dr. Michael Eisenberg** (3:00)
Yeah, I think that's fair to say. I mean, I think there's, you know, there's things that we talk to patients about. I think just sort of broadly when they come into the clinic, you know, obviously, you know, patients come to see me for fertility, they want to figure out how to get better sperm counts, right? And I think that's ultimately what our goals are. So I think, you know, lifestyle, you know, health, I think all those things are going to come at play. I always tell men, anything is good for your hearts, good fertility. So we talk about diet, exercise, maintaining good body weight. So, you know, I think things that you can do, you know, like whole grains, fruits, vegetables, I think those are important, you know, try and spend more time, you know, walking around and, you know, less time on the couch. I think those are sort of easy, actionable things. I mean, I think to the extent possible, try and limit exposures. You know, I think we've gotten a lot more awareness of, you know, some of the harms of, like, plastic, so trying to minimize, like, plastic water bottle exposures.