HIIT for Everyone

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Before I get into this study on high-intensity interval training or HIIT, I want to be sure you understand that unless you’re under 30 and very fit, you need guidance and advice from your physician before you attempt a HIIT program, especially if you have cardiovascular disease, diabetes, or are on medications for these conditions. I’ve been doing interval training for over 40 years, but the intervals I do today are within the limitations of the body I have today, not the limitations I had in my 30s. With that in mind, let’s proceed.

HIIT After a Heart Attack

Researchers in China recruited over 200 subjects with a specific cardiac profile: the subjects all had myocardial infarctions (commonly known as heart attacks) that were resolved by a percutaneous coronary intervention (treatment used to open blockages in the coronary arteries) such as a stent. This group requires special attention in that they are at serious risk for another event within the next year.

As part of a 12-week cardiac rehabilitation program, researchers divided the subjects into three groups:

  • A moderate-intensity continuous training group (MICT)
  • A HIIT group
  • A group that did a combined MICT and HIIT program.

The advantage is that every exercise session was under the supervision of professionals trained in cardiac rehab who knew how to respond if something went wrong.

All groups improved their fitness levels, but the combined training program of MCIT and HIIT provided better results than either of the approaches done separately. From a fitness perspective, those in the combined group increased the amount of oxygen they could use by more than the other groups and pumped significantly more blood per beat. Most important, there were no differences in major adverse events.

The Bottom Line

I specifically chose this study because these subjects were most at risk. With a doctor’s approval and under the right supervision, they were able to do HIIT safely. For most of the rest of us, those are obstacles and advantages we don’t face.

We should be prudent and check with our physicians first. We should also get some guidance on how to begin a HIIT program; if possible, get an appointment with a physical therapist to plan your workout program, because they’re trained to understand and work around everyone’s physical limitations and avoid injury. The workout plan must be within our fitness level right now, not 20 years ago. It can be as simple as walking faster for 30 seconds at a time during the walk you already take, but the gains can be significant toward improving our healthspan.

What are you prepared to do today?

        Dr. Chet

Reference: Aging and Disease. 2025. http://dx.doi.org/10.14336/AD.2024.0642

HIIT at Any Age

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Last week, I talked about taking inventory of where your body is now, primarily in your ability to move your limbs. The reason was that regardless of age as well as physical limitations, you can improve your fitness level; better yet, you can potentially accelerate the process using high-intensity interval training, also known as HIIT. It may take ingenuity if your physical limitations are significant, and you should be guided by your healthcare professional to get started. Let’s take a look at a recent study.

Researchers in Australia recruited a group of apparently healthy subjects 65 to 85 years old to participate in a HIIT study focusing on changes in body composition. With a mean age of 72, the subjects were randomly assigned to one of three groups: a control group who focused on stretching and balance exercises, a moderate intensity group who walked on a treadmill for 45 minutes at a specified target heart rate range, and a group who walked 40 minutes including a 10-minute warm-up, four 4-minute intervals at a specified heart rate range interspersed with 3 minutes of active recovery, and a cool down.

There were significant changes in body composition between the control group and both the HIIT and the moderate-intensity group with a specific change in the visceral fat. Were they fitter? The HIIT group had a greater use of oxygen than the moderate group, but it was not statistically significant. The important point was that even people over 80 could perform HIIT based on their specific fitness level. What about people who recently had heart attacks? I’ll tell you about another study on Saturday.

Tomorrow night is the Insider Conference Call, and the topic of the night is reducing the risk of dementia by changing the lifestyle factors that are under our control. You can participate if you become an Insider by 8 p.m. Eastern Time tomorrow night.

What are you prepared to do today?

        Dr. Chet

Reference: https://doi.org/10.1016/j.maturitas.2025.108763

Your Independence Inventory

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I’m breaking this into two separate inventories: your physical inventory, focusing on muscles bones and joints, and your logistics inventory. Let’s begin with your physical inventory. To make this easier, we created a printable checklist that you’ll find in the Basic Health Info section of drchet.com.

Physical Inventory

Let’s start with some of the factors that can impact your ability to exercise, whether that’s getting fitter, stronger, or more flexible:

  • Can you sit and stand without assistance? Do you need assistance whether in the form of a walker or arms on the chair? All of those require basic muscular strength and balance.
  • Can you walk without assistance? How about with assistance? How far can you walk? I know this sounds so basic, but everyone starts somewhere. How fast you can walk also matters.
  • Can you bend over at the waist? Do you lose your balance if you do that? How about squatting? Full squat, half squat, quarter squat, or not at all?
  • Can you get on an exercise bike or an elliptical trainer or a treadmill? In order to use them, you have to be able to balance well enough to get on them first. If you’ve never been on a treadmill, you don’t really know whether that’s possible for your fitness program or not. Some people have balance issues they never knew existed.
  • Can you stand in place with your eyes closed, or do you get dizzy? Can you touch your finger to your nose with your eyes closed while holding your arms horizontal to the floor? This test may be associated with assessing your degree of drunkenness, but you’ve got to be able to do it sober first.
  • Can you raise your arms above your head? Can you bend your arms at the elbow? Can you do a bicep curl with a can of vegetables? Can you lift it above your head?
  • Can you usually grip the lid of a sealed jar well enough to open it? Everyone’s grip strength deteriorates over time, so it’s important to know where you rate.
  • Can you get on the floor on your hands and knees? Can you lie face down on the flood? Can you lie face up? Can you get up off the floor without leaning on any piece of furniture?
  • Can you walk up a flight of stairs? Can you walk up a single stair and step down again?

Logistics Inventory

Logistics for getting healthier requires that you assess your assets and liabilities. You’ve got to know whether you have the time, the equipment, the time, the space, the time, the gym membership, the time… Are you getting the idea that time is important here? That’s the single biggest reason people quit an exercise program, and for most, it’s the reason they never start.

  • Do you have the time in your schedule, while getting reasonable sleep, to exercise? Early in the day? Lunch? Before dinner? In the evening? Every day? Three days per week? Does it depend on your children’s after-school activity schedule?
  • What equipment do you have? Do you like it enough to use it? Do you have exercise tubes or bands? Weights like dumbbells or barbells? Do you have mats for floor routines? Do you like exercising while watching videos or do you prefer music?
  • Are you a member of a gym or club? Can you get there on a regular basis? Is there enough equipment to do what you like to do? Does it have a pool in case swimming is your thing?
  • Do you have the time to prepare meals if eating better is your goal? Do you have a selection of the right tools to cook well? It’s easier if you have the right spices, knives, cookware, and cook wear (might as well have a cute apron). Do you have the budget to buy healthier ingredients?
  • What are you willing to eat on a regular basis? I’ve made it clear I’m not drinking smoothies or eating bars, at least, not very much. That means it takes more time for prep and cooking.
  • If you’re not exercising at home, is your car dependable?
  • Do you live in a safe neighborhood to walk or jog?

Those are just some of the logistical factors to consider before you get to working toward your health goals.

If you’re thinking this is just for old people, nope—I suggest you do this no matter what your age. Mark your calendar to inventory your physical state every year when you get your annual physical. You may find that although you’re only in your 30s, you can’t easily get up off the floor. The time to work on that is now; don’t wait another decade or two to work on your physical independence. You’re building your health future. Take a full inventory before you start your plan; that’s the way to gain the health independence we all want to have.

What are you prepared to do today?

        Dr. Chet

Time to Take Inventory

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After last week’s Memo on Independence, I decided to follow it up with some thoughts on where to begin the quest for independence. Nobody is beginning at absolute zero. Regardless of where you stand (or sit) with your health, it’s time to take an inventory.

I could include everything from lowering cholesterol, sleeping better, or reducing medications, but those are discussions you need to have with your physician first to see if what you’re planning to do is reasonable. They know what health issues you’re facing, from auto-immune diseases to type 2 diabetes, and even more. For example, if you have a genetically determined high blood pressure, you may have to stay on medications no matter how much weight you lose and how fit you become. I would start with a consultation with your physician or healthcare professional.

Once you’ve done that if it applies to you, it’s time to take inventory, both physical and logistical. We’ll do that on Saturday.

What are you prepared to do today?

        Dr. Chet

Two Questions on Independence

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I spend a lot of time observing people; I can spot someone with a gait problem whether the cause is their lower back, a knee, or an overall core issue. I also watch people move who have weight problems, especially young people in their 20s, 30s, and 40s carrying extra weight. Degenerative diseases aside, what kind of life will they have in their 50s, 60s, and 70s? I’ve watched what that does to people as well. I know from experience what carrying an extra 30 pounds is like. What must 100 or more extra pounds be like?

I’ve discussed the how of weight loss many times: eat less, eat better, and move more. But it really comes down to making the decision: 

            How independent do you want to be?

It’s one thing to become dependent on others due to an accident or other issue; it’s another to voluntarily give up your independence without gaining as much control over your body as you’re able. Think about that as we celebrate Independence Day this week.

Independence Day

I try to keep the Memo free from all other issues other than health and the things that can impact health, but I’m going to make an exception this one time to answer this question:

            Can we rely on U.S. election results?

I’m an election worker in my county in Michigan. I’ve been doing that for about six years. I’ve read what people say about elections, and for the most part, they don’t know what they’re talking about. The system is set so that only registered voters with proper identification can vote (and we’re really good at enforcing that), and those votes are protected throughout the election process, even after they are counted and reported.

Here in Michigan, the Heritage Foundation analyzed 17 years of data, 26 elections in total, and in almost 65 million votes they found 19 cases of reported (not adjudicated) fraud, or 0.0000294%.

Here’s my challenge. If people question an election, they should become a part of the process. Become a poll worker, election worker, or election inspector in their county. Use that one day during primaries and during the national election in November to be a part of the process. Yes, there will be some training beforehand. Yes, it can be a long day or days. But if anyone wants to be sure the process is fair and free, they should be there in person and watch it firsthand. Regardless of anyone’s political persuasion, if they won’t do that, anything they say about the election process is meaningless. Feel free to forward this Memo to anyone who repeats the theories without participating in the process. Time to ante up if we want to keep our elections free and fair.

Enjoy the 250th celebration of our country’s Independence!

What are you prepared to do today?

        Dr. Chet

In Case You Ever Wondered

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Many of you probably don’t remember William Proxmire, the U.S. Senator who criticized government-funded studies five decades ago. Another senator, Tom Coburn, picked up the mantle in 2010 by criticizing research on greenhouse gases from cows. (It’s bipartisan; we’ve got one Democrat and one Republican.) While the research was not about flatulence—cows don’t fart—it was about belching, which cows do, evidently a lot. The cows’ emissions were found to contribute to methane production, which can impact our atmosphere.

Not to be outdone on noxious emissions, the Australian researchers decided to ask the question: how many times per day do Australians pass gas? An Australian research group created an app where people could report their fart frequency. Seems ideal for a group of 8- to 12-year-old boys; they would make it a competition, especially when you call the app Chart Your Fart. Alas, the researchers must have realized that and set the lowest age limit at 14. The researchers promoted the app over various media to the extent that over 6,000 people qualified and participated in the study. The app is still available although the study is closed.

The average number of gaseous explosions? Five per day for both men and women (although some women may disagree with that number for their husbands). What was interesting is that flatulence followed several hours after eating. And the more fiber a person reported eating, the more gas was produced.

It makes sense. What does fiber do? Feed bacteria and other microbes that live in your gut. How do they make energy and perform their job? Fermentation, and fermentation produces gas. It’s completely normal. One more interesting result. The age group that farts the most is 26- to 45-year-old men. Knowing that, my life is now complete.

What are you prepared to do today?

        Dr. Chet

Reference: JAMA Net. doi:10.1001/jamanetworkopen.2026.15637

Sun and Soup

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A long-time reader pointed out that I made a mistake in Saturday’s Memo: the earth is not closest to the sun during the summer—in fact, depending on the minute, it’s at the furthest point from the sun. I confess I did not check the science on that one. It just made sense and therein lies the problem; science doesn’t always work that way. The reason the Northern Hemisphere is warmer in the summer is the angle of the earth in relation to the sun allows more heating rays through the atmosphere. I always want you to call me out when you think I’ve made a mistake. If it’s a fact, I’ll admit the mistake. I always check the science related to health, and I’ll make sure I do it in all areas of science. Thanks for checking me.

In light of the recent obsession with algae, Paula reminded me that we have a Recipe section on the website, and that’s where you’ll find a recipe called Pond Scum Soup. It’s a great-tasting soup that is chock full of phytonutrients. I like it because I get to use my stick blender, but it does look like green algae floating in a pond. The dead fish are optional.

Saturday, I’ll give you a run down on studies nutritionists don’t want you to know about. Enjoy the soup!

What are you prepared to do today?

        Dr. Chet

Reference: https://spaceplace.nasa.gov/seasons/en/

Protect Your Skin

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Astronomical summer begins tomorrow morning at 4:24 a.m. EDT in the Northern Hemisphere, the point when the earth will be closest to the sun. Because it will also be the longest day of the year, it will also provide the greatest exposure to the sun and its ultraviolet light if you’re going to be outdoors. Of course, our friends in the Southern Hemisphere need protection from the sun, too, even though winter sun isn’t as harsh. Protecting your skin is a year-round effort, so let’s see what all the fuss is about with the approval of BEMT.

Safety Consideration

I checked the PubChem database for BEMT (short for bis-ethylhexyloxyphenol methoxyphenyl triazine, AKA Bemotrizinol or Tinosorb-S). There were no safety issues with any of the 144 studies that are typically done for new chemicals. Further, the FDA document did not find any safety concerns in any of the animal or safety trials. It had minimal systemic absorption with rare, mild adverse events. There was also no evidence of androgen- or estrogen-receptor binding that had been a concern with other sunscreen ingredients in the past. BEMT is considered safer for babies and small children and for people with sensitive skin.

The FDA has approved this chemical as Generally Regarded as Safe at no more than a 6% solution. That means it’s not a pharmaceutical and will be regulated the same as dietary supplements.

Why It May Provide Better Protection

Besides the safety considerations, BEMT appears to be photostable, which means it doesn’t have to be applied as often throughout the day. One of the features is that it doesn’t appear to leave a white cast on the skin, so you can keep looking great. The most important feature is that it maintains the photoprotection longer. Consistent use over time will reduce the risk of sunburn, aging skin, and skin cancers.

While I looked, I could not find any data to support a benefit in the reduction of skin cancers in the countries that have had it available; no one has decided to find out the answer to that question yet. Perhaps with its introduction in the U.S. market, a graduate student will take that on as a question to be answered.

The Bottom Line

The only downside to the new sunscreen ingredient is that it will take time to find its way into the current marketplace. It’s been available on the internet for a while, so you can get it wherever you are. Whether you use the current products or add the new ones that will inevitably follow, I believe it’s important because it will reduce the inflammation caused from skin damage by UV rays—and we all know inflammation of any kind is the enemy. Every bit of inflammation we can reduce will improve our immune systems, and that will help our entire body.

What are you prepared to do today?

        Dr. Chet

References:
1. https://pubchem.ncbi.nlm.nih.gov/compound/Bemotrizinol
2. https://iit.msu.edu/news/2025-12-16-CRIS-in-the-news-bemotrizinol.html
3. https://www.accessdata.fda.gov/drugsatfda_docs/omuf/order/supportDoc/OTC000039/2.2_Introduction_to_the_Summary_Documents/rev_introduction_090026f88e1259aa.pdf

New Sunscreen Ingredient

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Bis-ethylhexyloxyphenol methoxyphenyl triazine! Say that five times fast. Heck, say it fast once! No, this isn’t a memo about tongue twisters; it’s about the FDA finally approving a new ingredient for sunscreen in the U.S. A simpler name is BEMT, bemotrizinol, or Tinosorb-S.

Why a new sunscreen ingredient? It not only neutralizes the free radical damage to skin by UVA rays, which can lead to cancer and aging, it also absorbs the UVA rays which cause sunburn. It has been used in Australia, Japan, and European countries since 2000. You’ll most likely find this ingredient in high‑SPF and high‑UVA‑protection blends.

I’ll go into more specifics on Saturday, including safety data and why it may be a better option for some people.

Tomorrow night is the Insider Conference Call. I’ll discuss three new topics that have caught my attention: a condition known as Ozempic mouth, a new study on food colorings and additives, and just for fun, why nutritionists have dissed the use of high-fat ice cream—it’s not why you think. Become an Insider by 8 p.m. to join in the discussion and get your questions answered.

What are you prepared to do today?

        Dr. Chet

Creatine and the Unasked Question

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If you read the article on creatine posted by the AMA, while as short as a sentence or two, the points were valid. Let me elaborate on a couple of the ones I think are most important.

Creatine Builds More than Muscle

The point they were making is that creatine may be beneficial to build muscle in those over 65, but that’s not all. I checked the study on the relationship between creatine intake and memory in persons 66 to 76; while it’s a meta-analysis and those can be potentially biased in the way studies are chosen for inclusion in the analysis, the data showed that memory was improved compared to a younger population.

The question is why? My personal opinion is that creatine may increase the production of energy in nerve cells in the brain, which can help learning and memory. There’s also the possibility that creatine may help increase the fluid content of brain tissue, thus making the cells work more effectively; we do tend to dehydrate more as we get older.

The second important point was that creatine is safe to use for nearly all of us, provided we don’t have chronic kidney conditions. While there have been a few small studies that have shown that even in people with diabetes-related kidney failure, creatine can be safely used, it’s best to work with a physician/specialist if you’re in that category of kidney disease. They can check creatinine levels to make sure kidney function isn’t being harmed. For the rest of us, using 3 to 5 grams of creatine every day seems to increase the benefits of muscle repair and growth with weight training.

The slight water retention and digestive issues mentioned are minor issues that typically resolve themselves when compared to the benefits creatine may generate. Just remind yourself that if your brain is retaining a little water, that’s a good thing!

The Unasked Question

What’s the question no one ever asks in nutrition studies? “How did you feel while you were taking the supplement?” Feelings can vary depending on the supplement: more energy, better sleep, fewer digestive issues, and on and on. I’m not talking about filling out questionnaires or taking tests. We’re all grown up enough to know that you may feel a little worse at first, but it usually goes away with time, so don’t get in a hurry to give up on creatine.

Simply, “How did you feel?” At the end of the day, that’s what’s really important to the person taking the supplement. Too often, because there are no real “hard science” tests for how a person feels, it’s not asked. We simply don’t know everything about how every food, every supplement, and every pharmaceutical impacts every tissue in every organ in the body. Sometimes, it’s just about how you feel day in, day out.

What are you prepared to do today?

        Dr. Chet

References:
1. https://www.ama-assn.org/public-health/prevention-wellness/9-things-patients-should-know-about-taking-creatine
2. Nutr Rev. 2023 Mar 10;81(4):416-427. doi: 10.1093/nutrit/nuac064.