Episode 33: HIIT Hype vs. Your Hormones: A Midlife Game Plan

Is more HIIT always better? Dr. Angela breaks down what the science really shows—and what it doesn’t—about high-intensity interval training after 40. Most trials that find big benefits use three sessions per week or fewer and consistently show improved fitness, cardiometabolic markers, and reductions in overall fat mass. But there’s no direct evidence that cranking HIIT beyond that helps midlife women (or men) lose more fat, and none proving it harms hormones either. In this episode, Dr. Angela defines HIIT clearly, explains why perimenopause changes fat distribution, and lays out a balanced weekly plan: strength as the anchor, Zone 2 for your aerobic base, and HIIT used like hot sauce—powerful, not daily. Plus simple recovery guardrails to know when to pull back. Smarter training, better longevity, fewer aches.

Transcript

Dr. Angela: [00:00:00] Hello, this is Dr. Angela. Welcome to another long awaited episode of the Lifestyle md. In this episode, I'm going to expand on a blog post that I recently put out as part of the Lifestyle md, and it's with regards to high intensity interval training. I've got some caveats. I've bringing some new information to this podcast episode, so you're not gonna wanna miss it.

I have had women come to me both in my practice when I was working for the healthcare system and when I started my current practice with this reoccurring theme of I am doing training. I'm weightlifting, I'm doing high intensity training. A lot of them are participating in gyms that have regular scheduled classes.

They're lead, they're group, they're really putting in the work, they're building muscle, they're getting stronger, but they're complaining that their midsection isn't moving. They're not seeing the scale, the number on the scale change. Well, you are not alone, you're not broken. And I also wanna tell you that it's always not, or it's not just about the number on the scale.

One factor may not be [00:01:00] improving, but there are other things that are transpiring inside of you that you may be overlooking. Frequent high intensity interval training may not be best for you, especially if you're a woman over the age of 40, if you're per menopausal.

The reality is there is no direct scientific research that shows that training greater than three times per week doing high intensity interval sessions actually is harmful to you. There's no evidence that it makes it harder to lose fat. There's no evidence that it has a negative impact on your hormones.

I will say that does not mean that it isn't true, just means that no one has actually studied it, published about it, maybe not done the rigorous research. Anecdotally, I've seen that that can be the case. Most trials that have been published, and I've gone through and looked at the literature just, reviewing PubMed and trying to analyze the data or at least quickly parse through the data.

Most of the trials heavily focus on three times a week or less, assessing the benefits [00:02:00] of high intensity interval training and have reported significant benefits.

Today I'm going to share with you what the science does show and how we can translate that to a healthy plan. But I'm also gonna show you what the science doesn't show, and it may not just be because it's proven it to be wrong. It just hasn't investigated. So stick with me. All right, so in this first section I'm gonna define to you what is high intensity interval training in the first place.

What is high intensity interval training in the first place? Is a workout style that alternates short burst of vigorous high intensity effort performed at around 80% of your maximum heart rate or near maximum effort. So it can be even higher that with periods of rest or low intensity activity in between.

So the intervals, your work interval is usually anywhere from 30 seconds to four minutes. It can include things like sprinting, cycling, rowing, heavy weightlifting or moderate intensity weightlifting, the recovery period is usually equal to or longer allowing for just [00:03:00] partial recovery, so you're not gonna go into the next round, fully recovered.

Your total session length is usually anywhere between 15 minutes to 30 minutes. 30 minutes is pretty typical. And the goal of it is to improve your cardiovascular fitness, your insulin sensitivity, your fat oxidation level, and it's supposed to do it more efficiently and more effectively than traditional steady state cardio.

Now, there are some studies out there that have compared steady state cardio to high intensity interval training and high intensity interval training does have some superiority there, so let's get more into that detail.

So here is the big picture snapshot of evidence around the benefits of high intensity interval training across all adults, obese, overweight, people who have experience with training, people who don't. High intensity interval training does improve your VO two max. That is a very popular phrase that you might be hearing around, longevity circles.

It's something that we're using as a measure now to predict someone's [00:04:00] health and wellbeing and their longevity. So, high intensity interval training is very good at improving VO two max. It is also an excellent way to lower your cardiometabolic risk factors and reduce fat mass, but it is not consistently superior to moderate continuous training or like the low steady state cardio for improving abdominal visceral fat.

Okay, let's rewind that. So what does the evidence clearly seem to show across all adults from healthy athletes all the way to those who are overweight and obese and those who are not.

HI training improves VO two max and cardiometabolic risk factors, and it reduces overall fat mass. It has been associated with improved longevity. So that's something that you may care about, but it is not consistently superior to moderate continuous training.

Something called MICT for abdominal or visceral fat. So if we're specifically trying to target visceral fat or abdominal fat, this is not necessarily [00:05:00] superior based on the current evidence. So what does this mean practically? High intensity interval training works, but so does steady state cardio so you don't have to completely replace one with another.

This is good news because I highly recommend variability in your training, and if you are someone who's followed CrossFit or been following high intensity, as this has kind of come to popularity, you will find that most programming incorporates a little bit of all that and isn't strictly just about high intensity interval training.

Fun fact, high intensity interval training did not start with CrossFit. it actually has been around since, as early as the 1920s, there was a Finnish Olympian, I'm not even gonna attempt to say his name, but he incorporated interval training into his running.

So most people, will ascribe the origins of high intensity training to cycling and running. And that accounts for kinda like the very beginning.

It really had its commercial boom with the [00:06:00] adoption of these methods, in CrossFit, Barry's Bootcamp, orange Theory. So this whole concept of high intensity interval training is actually nothing new. So we actually know a fair amount about how effective it is, and it has been really good at helping athletes improve their performance.

And I'll tell you, when it comes to me and training, especially later in life when I wanna do running, I spend very little time actually running the actual distances of my races and doing a lot of my training in interval work. But I digress.

Bottom line here is that HI is effective. But in head-to-head comparisons, it often ties with steady state cardio with regards to fat loss, especially around the midsection. So if you are specifically trying to lose midsection weight, high intensity interval training is not necessarily gonna be better then doing steady state cardio or doing moderate intensity exercise.

What don't we know about high intensity oval training? Over the course of the last five years, I've really been curious, to understand [00:07:00] why my middle age and per menopausal women are having a hard time with losing weight. The medical industry and popular culture has taken definitely a greater interest in understanding women's health and how perimenopause and hormone changes affect body composition, cardiovascular risk, and even weight loss and visceral fat composition.

What's happening during menopause Perimenopause, your estrogen is declining and that is leading toward a shift of favoring, pushing fat toward the visceral body fat or towards the midsection, and that's gonna lead to higher cardiometabolic risk. Men are also at risk of this. The impact of them is kind of like slower and more steady decline as opposed to abrupt drop off, but they are also at risk.

Okay? So even if the scale isn't moving, body distribution does change. And if you are still weighing the same and you're in that perimenopause, but you're noticing more midsection fat, that is a huge marker for cardiovascular risk. So, being thin or [00:08:00] maintaining your weight, but having more midsection fact.

Means that you're actually at more risk. So when I talk to patients about what we're trying to accomplish with dietary changes and with weight loss, I want you to focus on not just the number on the scale. I want you to focus on your body composition. Okay? So what don't we know and what shouldn't we claim?

There are no direct trials that are looking at premenopausal, perimenopausal, menopausal women and testing the impact of high intensity interval training greater than three times per week. There's no trials that look at the long-term impacts on cortisol, insulin sensitivity, and sex hormones.

Most trials show a positive impact on HI training if you're doing it three times a week or less. Most of the samples they're looking at are younger women and also men. There are some that look at different ages in more heterogeneous populations, but there's nothing specifically targeting that age group.

So right now, I can't [00:09:00] say with certainty that this is a problem, but what I can say is that if we go with the data that we have, you shouldn't be doing it more than three times per week. 'cause we have no evidence to support that. It's really even beneficial. It may be, but there's no evidence to support that.

We do not have cause and effect data that too much hit training raises cortisol chronically, or blocks fat loss for women over the age of 40. That's a hypothesis that I have and it is not evidence-based. Having said that, we also don't have any evidence that it's a good idea.

So my firm recommendation is that if you are. Man or woman over the age of 40, you should be limiting your high intensity training to three times a week or less because that is what the data shows is beneficial.

So why should you still not make high intensity training the base of your workouts even though we know it's really potentially helpful, we know that there cardiometabolic benefits. We know that there's VO two max benefits. We know that it can actually more [00:10:00] efficiently help you reach your fitness goals, especially if you're a competitive athlete.

Why don't I still recommend that you make that the base of your workouts? And what does that mean to be the base of your workouts? The majority of your workouts are kind of surrounded by that. Well, for one. Midlife in older adults. The mainstream guidance right now is recommending that you have weekly aerobic, cardiovascular training in about two days a week or more of strength training.

It doesn't currently mandate any high intensity training. Now, I don't typically always go by the guidelines. The guidelines are a good starting point, but they are usually just trying to appeal to the. Mainstream population and go with things that they can say with certainty. So, with certainty, we can say that this is healthy.

Training principles too is that recovery capacity varies by person. So if you are someone who does not have a [00:11:00] baseline level of really good fitness, or you are not doing a great job in the recovery phase, the more high intensity training you're doing, the more frequently you. Increase the risk that you are over training and predisposing yourself to injuries if you are raising the intensity, but not raising your recovery efforts

I just had a conversation with one of my patients who has complained about feeling more aches and pains and tightness and having all these issues, I acknowledge personally and for her that it's very easy to get excited and do all that high intensity training, but then to just gloss over the recovery period, gloss over the importance of doing yoga, light stretching, mobility work.

It is even more critical as you get older to incorporate those things as a part of your routine. So you can't exclusively do the intense training. You must also do the recovery work. So the final point about this is that high intensity [00:12:00] isn't clearly more superior for improving visceral body fat compared to the moderate intensity exercises.

Because of this, it is reasonable to use it strategically and not daily. So in other words, having one, two, maybe three days a week. My favorite numbers two, as it pertains to high intensity training that you're doing high intensity interval training. Then you're going to give yourself low intensity, moderate intensity other days of the week.

My first concept of this came from my bodybuilding coach when I was doing bodybuilding training. She adamantly did not allow us, and many of her clients were middle aged and older women high intensity interval training more than one day a week. Consider that.

Bottom line because steady state cardio matches high intensity interval training for belly fat loss in many of the studies that are out there right now. Strength is essential for muscle, maintenance and bone strength and bone density. I like to use high intensity training as [00:13:00] like the compliment to the meal and not the main course.

So I strongly encourage you to incorporate it, but not to make it the main focus of all of your fitness programming.

So let's bring this together. What is a practical weekly template that you can use when you're thinking about your training? You can start with an anchor. So two to four sessions per week where you are working on preserving and building lean mass. So just doing, strength training work with, adequate rest between sets so you're recovering enough to be able to complete subsequent sets at the same intensity.

With the same form without compromising and creating injury risk. Then I would recommend having an aerobic base zone two training where you're. Trying to get in up to 150 minutes per week of moderate, cardiovascular [00:14:00] training. You can do that with walking, cycling, hiking, rowing, any type of thing that is primarily a cardiovascular, workout that is important to include into your weekly regimen.

And then finally. High intensity interval training, one to two sessions per week. So that aligns with, the recommendation of less than three, or three or less. And it also allows you to separate those training days by 48 hours or more, which allows you to safeguard yourself from injury and allow for adequate recovery.

Here's a sample regimen that you could adapt for your purposes. Monday lower body strength training. Tuesday, 30 to 45 minutes of zone two cardiovascular training with a brisk walk, bicycle ride, light run. Wednesdays high intensity interval training [00:15:00] followed by a short mobility workout. Maybe 10, 15 minutes just to cool down Thursday, upper body strength followed by 20, 30 minutes of easy cardio.

And then Saturday long walk or hike in zone two. So you notice that each one of the days isn't strictly dedicated to just one of the activities when it comes to cardio. The best way to squeeze it in is to tack it on the end of one of your workouts or use it as part of your warmup so that you're kind of building it in and using it as a means of warming up and cooling down.

Now this is not a regimen for everyone. I strongly encourage you to work with a trainer. I'm going to be interviewing, a dear friend and someone who is also a part of my coaching team right now, and she is a coach for a program called Faster Way. If you are looking for some guided instruction on how to do something just like this, I encourage you to check that out.

So listen for that next episode, which will be coming up shortly where you can learn more about [00:16:00] that. What is the point of all this? Why am I even talking about high intensity interval training? Why am I talking about midsection fat? Visceral fat is that if you're going to do the work, you need to know that it's working.

Just tracking your weight on the scale is not enough, and even if it's going down, wonderful, that's one metric, but it's only one metric. I want you to make sure that you are also thinking about the bigger picture. Exercise is not. All there is, you need to make sure that you are, getting good sleep quality, that your ability to rest is not compromised by your training.

So what is the point of all this? You wanna make sure that you are actually achieving your goals. I would argue if your only goal is to lose weight, then you need to expand your goals a little bit more. So improve longevity, reduce visceral body fat, improve cardiometabolic risk factors, and all of that you can discuss with your physician.

In our practice, seeds of Health through primary care, we have a body [00:17:00] composition scale. I really love tracking visceral body fat. We also track things like insulin to monitor insulin resistance in addition to the traditional markers of cholesterol, liver function, kidney function, diabetic screening.

So if, depending on where you are and what's happening with you, I would recommend, first of all, partnering with your clinician to make sure that you're improving your health, more broadly than just losing weight. The other thing is you wanna make sure that you are monitoring how your exercise is affecting you,

place guard rails around your routine. I do not recommend that you push through doing the training if it's having negative impacts on you in other ways. If you are noticing that you're having disruption in your sleep quality, because maybe the timing of your workouts isn't aligning with your schedule.

If you are feeling, that you're having more irritability or fatigue, if you're losing your drive to train because you're not looking forward to it, then you've gotta change something. If you are finding it difficult to hit your training goals and so you're doing a workout and you could hit [00:18:00] your. Reps, or you could hit the weight and now you're not.

There's something wrong there. So again, take a step back and use these as cues that you need to either pull back on the intensity, pull back on the frequency, just make some sort of adjustments to your schedule. If you're not working with a trainer, I think that would be a good time for you to consider working with someone.

Other things to look for, especially if you are, later in life is, without having lab values, like not checking things like testosterone, estrogen, progesterone, you can kind of assess like for men and women. Is your sex drive improving, not improving? Is your energy level improving, not improving?

Are you noticing changes in your mood and energy patterns? Are you having more or less hot flashes? So exercise can actually modulate the symptoms of perimenopause and menopause in a good way. It can improve testosterone in men who are struggling with low testosterone, so getting more strength training.

Getting more moderate and high intensity training can actually boost and improve your testosterone numbers. So there are lots of things to think [00:19:00] about when you're thinking about why you are doing what you're doing. It's not just about the weight loss, it's not just even about the visceral body fat.

It's so much more than that. What do I want you to take away from this? Well, we know. High intensity interval training works in moderation. Steady state cardio and strength training are also rock solid. There's lots of evidence to support that. The perimenopause shift in women, which shifts more towards storing fat in the abdomen means that you're gonna want to do something that is going to favor the modulation or reduction of that.

And for that reason, we know that high intensity interval training is not superior steady state cardio I can't speak to the research in men right now, but I can tell you that that's the case. Doing three days per week or less has been consistently shown to be effective, and even the American College of Sports Medicine recommends doing three days a week or less of high intensity interval training.

There is no evidence that doing more than that is [00:20:00] disruptive to your ability to lose fat. Or to reduce insulin resistance, but there's also no evidence to say that it does help. So I would recommend sticking with that three days a week or less. I would recommend building fitness programs and guidelines that protect recovery, especially in older adults.

In between, because we're not just talking about strength, we're also talking about joint pains and injury prevention and back problems. We want to make sure that you have adequate time to heal and allow your muscles to recover. Before you jump from one workout to the next. So use high intensity interval training as a tool, but not as the foundation of your fitness plan.

All right, I hope you found this helpful. If you are in the Grand Rapids area, you're looking for a primary care doctor.

I'm not a coach. I really enjoy medicine. But I also like having these conversations with my patients. So if you are looking for a physician who think about the whole picture, and not just chronic disease management and treating diseases, but preventing them and [00:21:00] reversing them.

I'm your woman. So looking forward to next time. We've got a lineup of awesome guest and I can't wait to bring them on the show. Our very first, guest coming up will be, Marcy. You'll get to hear more from her about the program I mentioned earlier, which is the faster way. I think that's something that might be useful for some of, you're looking for some guided, trainings and also some nutrition help.

So take care. Have a good one. Bye.