H E A L T H L E T T E R No. 2

Issue No. 2 - June 2024

-Keep Your Brain Healthy

-The Longevity Inventory

-Aerobic Threshold

-Protein & Muscle

QUIZ: What's the best way to keep your brain healthy for life?

(a) Check apo E

(b) Eat more sardines

(d) Something else

The best answer is to keep your blood vessels happy. I know — blood pressure isn't nearly as fun as sardines or Apo E! But it's the number one risk factor for cognitive impairment in aging adults. High blood pressure dings up blood vessels and can eventually cause microvascular changes in the brain.

Though the default is to use medication to control blood pressure – there are 61 FDA-approved medications for hypertension - there’s also strong scientific evidence that exercise reduces blood pressure and is healthy for your brain long term. A study of 19,000 adults found that those with the highest levels of cardiac fitness in midlife were much less likely to experience a decline in cognitive function three decades later.

Introducing the Sequoia Project Longevity Inventory

Dozens of studies have shown that regular exercise improves overall health. So I’ve wondered why we have universal physical fitness testing for children – remember the 4th grade shuttle run? – but there isn’t an equivalent for adults. In adults we check tests like blood glucose, cholesterol levels, and everyone's favorite, the BMI, which can really only suggest the presence or absence of disease.

What about validated measures to evaluate health? You may know there’s a considerable body of evidence showing that VO2 max, which measures maximum oxygen consumption, is a predictor of longevity. Evidence also suggests that higher lean mass and lower visceral fat can predict future good health.

Since we can’t routinely measure lean mass every time a patient walks in the door, I've developed an inventory to help track patients’ physical fitness with input from kinesiologist and fitness polymath Matt Jones. These metrics can be completed with minimal equipment. They are meant to help us understand your cardiac fitness, strength, and how well you use your body. If you're a patient 30 years or older and we haven’t talked about this yet, please touch base.

Having beta-tested the metrics, I can say it's easier just to get blood drawn or have an x-ray. Personally, I was not thrilled about giving maximum effort and falling short of where I wanted to be. But with this information, I am making some adjustments and will be very interested to find out where my numbers fall next time.

This inventory isn’t graded. It doesn’t measure something fixed like your genes. We're checking this stuff so you can see the trajectory you’re on and identify areas where you may want to pay more attention to optimize your physical health.

Know About The Aerobic Threshold

Exercising near your aerobic threshold, also called “Zone 2”, is fundamentally how you improve cardiac fitness.

Zone 2 is where you can exert yourself at a steady pace for a longer period of time. It should feel like a strain but not like all-out intensity. At this level, your muscles haven’t begun to produce lactic acid, which is what leads to the muscle cramping that makes most people stop. You can get zone 2 exercise from walking briskly, walking with extra weight (‘rucking’), hiking, running, cycling, swimming, and many other activities that require steady effort.

Working out just below your aerobic threshold trains your muscles to use oxygen more efficiently and progressively adapt to higher workloads. Being in this zone trains your muscles to burn fat more efficiently.

High intensity interval training and resistance training are complementary to exercising near the aerobic threshold and can accelerate your gains. We’ll tackle these topics another time.

Muscles & Protein

The next thing that naturally comes up is, what should you eat to improve cardiac fitness and lean mass?

To simplify some complex biology, muscles are built with protein and fueled by carbohydrates and fat. So you need all the macronutrients for optimal muscle performance — but I want to focus on protein for the moment.

It’s frequently reported that most Americans consume more protein than they need – at least men do – and it’s not healthy. Let’s unpack this. The longtime U.S. Recommended Daily Allowance for protein is 0.8 g protein / kg / day. Go ahead and calculate your number, but read the fine print: despite being called the “daily allowance”, this is the minimum amount a body needs to not lose muscle. Meaning the guideline is a good fit if you’re relatively sedentary and aren’t looking to get stronger.

The one-size-fits-all approach is where this breaks down. We now know that with age, adults become less efficient at using protein compared to their younger selves. Midlife women seem to experience changes with protein processing that can correlate with weight gain during menopause. And in the sixth or seventh decades of life and beyond, protein absorption and muscle protein synthesis become even less efficient, meaning you need to consume more protein just to get the same result.

What happens when you don't meet your protein needs? Well, the human body is efficient and meets its needs by reallocating resources. In short, you become catabolic, breaking down muscle to serve more critical body functions than crushing that bike ride.

Experts are now starting to apply decades of athlete nutrition research to active adults – a term that applies to everyone in this practice, even if you don’t consider yourself an athlete. If your goal is to build lean mass – and it is! – you likely need at least 1.2 g protein / kg / day (and less of the other stuff, which is a whole different topic.) To be clear, protein intake itself doesn’t build muscle if you’re not working those muscles. It’s only in the setting of exercise that your body can use protein anabolically, to increase lean mass. What can be tricky is if you’re trying to lose weight for health reasons while maintaining or gaining lean mass. If this applies to you, please check in with me before making dramatic changes, and consider working with a registered dietician too.

For an active 165-pound adult who works out with some regularity and intensity, this translates to 90-100 grams of protein per day. An egg has 6 grams of protein, a serving of tofu 9 grams, a handful of almonds 7 grams, and a 4-ounce steak 26 grams, so you will likely need to be intentional about what you’re eating to hit your target. (I recommend eating whole foods when possible, while understanding that additional calories are trickier if you're trying to be calorie-neutral or lose weight.) Fun fact: chicken breast is one of the most protein-dense foods, with more than 50 grams of protein in 6 ounces — great news for those who enjoy this part of the chicken.

Unfortunately, it's not as simple as just chowing down; there’s lots of nuance. For example, protein intake should be spread throughout the day for optimal uptake. Broken-down protein such as ground meat is easier to absorb than a hunk of steak, unless you’re exceptional at chewing. And while animal protein is the easiest source of “complete” protein, with all the essential amino acids, most animal foods also contain significant saturated fat, which is implicated in artery blockages. So it’s helpful to vary your protein sources and also seek out plant foods that supply essential amino acids including lysine. (Avocados are one such food.)

Professional athletes have shown it’s possible to eat vegetarian and even vegan and perform at a very high level. Check out my friend and ultrarunner Scott Jurek's book, Eat and Run, where he describes how he broke ultramarathon records while eating a purely plant diet. Worth noting: at his competitive peak, like many professional athletes, Scott was eating all the time – a level of food consumption that would be extremely challenging for anyone who goes to school, works a regular job, raises children, etc.

Finally, know that protein uptake and muscle synthesis are most effective within 24 hours of a cardio or strength training session. Take advantage of this physiologic tendency by getting in a short exercise session each day rather than saving up for the weekend.

The Upshot

Building cardiac fitness protects your brain’s long term health. Engaging in regular exercise near your aerobic threshold and linking protein intake to those sessions positively impacts your VO2 max and helps build lean mass while keeping your blood vessels happy. It all works together for your long term health.

And keep doing those hard math problems!