Is Zone 2 Really the Cardio Sweet Spot?

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Today’s Health Upgrade

On Our Radar
Can Lion's Mane Make You Smarter in 90 Minutes?

Mushroom coffee. Mushroom gummies. Mushroom powders. Everyone wants to know: is Lion's Mane actually doing anything?

A recent study suggests that hype might not match the science. Researchers found that a single dose of Lion's Mane did not boost overall brainpower or mood.

Researchers tested whether one dose of Lion's Mane (3 grams of 10:1 extract from the fruiting body) could improve cognition and mood in healthy young adults. The participants were tested on memory, executive function, attention, motor skills, and mood, both before and 90 minutes after consuming the supplement or a placebo.

While it’s just one study, there were no significant improvements in total cognitive function or mood. And on two executive function tests, performance worsened. 

It wasn’t all bad news, as Lion's Mane improved scores on the pegboard test, a measure of fine motor skills and hand-eye coordination. 

Lion's Mane appears in most mushroom-based products and rose to popularity largely on the back of animal studies showing it stimulates nerve growth factor (NGF), which supports brain cell function. But that's a slow, structural process, which is part of why the researchers say the mechanism behind any quick effect is still unknown, and why real benefits, if they exist, may take longer than a single dose to appear.

If you take functional mushrooms, the current research suggests you won’t experience an instant brain boost. 

And if you're taking Lion's Mane for long-term brain health, the strongest evidence so far is in older adults with cognitive decline, not healthy younger people, where the results are mixed.

Together With Our Place
74 Studies Later: What Forever Chemicals Are Doing to Your Blood

You've been watching your cholesterol. Cutting back where you can, checking the number when the bloodwork comes in, nudging it down. Here's a factor that probably wasn't on your radar: your exposure to forever chemicals. 

Across 74 studies, higher levels of two forever chemicals (PFOA and PFOS) tracked with higher total and LDL cholesterol in adults. 

Researchers at a federal health agency analyzed 74 epidemiological studies covering adults, kids, and pregnant women across ordinary neighborhoods and communities sitting near known contamination. 

The pattern for adults held up: the more PFOA and PFOS in the blood, the higher the total and LDL cholesterol levels.

The scientists believe that PFAS might interfere with the way your liver processes fat. 

But every study was observational, which means we're looking at correlation, not proof. And research has yet to show PFAS cause higher LDL in humans.

The bigger story is the same one we mentioned every time we discuss forever chemicals: you’re going to be exposed on some level, so the goal isn’t to panic. The poison is in the dose. 

Zero exposure isn’t a realistic (or necessary) goal, but limiting exposure where it’s practical can help reduce any potential risk. 

Water is one place to limit it. And you can filter that. Cookware is another, and it might be the simpler of the two, because it's a one-time decision rather than a habit you keep up.

When we went looking for pans made without these chemicals and backed by real testing, Our Place maintained the highest standards.

Their cookware has been made without forever chemicals since day one. The Always Pan, their most popular piece, uses a ceramic nonstick called Thermakind, made without PFAS, PTFE, PFOA, lead, or cadmium. That PFOA is the same one from the study above. It's also a 10-in-1, so it does the job of about half your cabinet. 

And when we tested in the kitchen, we appreciated that eggs slid off easily, meats and vegetables cooked evenly, and cleanup was simple. It's all third-party tested to meet global safety standards, so you're not just taking the label's word for it.

As a Pump Club reader, use code APC for 10% off sitewide. There's a 100-day trial, so you can cook on it and decide with nothing on the line.

Reader Question 
Do Women Burn 300 Extra Calories During Their Cycle?

Deb asked: I’m loving the Pump Club nutrition tracker. But I had a question: does this adjust for the metabolic changes women experience? I saw that women burn 300 more calories at certain points in their cycle.

Spend enough time on social media, and you’ll stumble upon one of the viral videos suggesting studies show that women are burning up to 300 additional calories per day during their cycle.

We looked up the studies, and the 300-calorie metabolic claim is not accurate.

During the luteal phase (the week or two after ovulation and before your period) a woman’s resting metabolism may increase slightly. However, a meta-analysis of 26 studies found that the effect was statistically insignificant.

And then another systematic review estimated that the increase can be as little as 30 calories and as much as 120 calories per day. And another 2024 study found that women burned only about 40 additional calories during the luteal phase.

Here’s why you don’t need to adjust dietary intake: those metabolic changes mirror the day-to-day metabolic variation everyone experiences. You don’t burn the same number of calories at rest daily. On average, your caloric burn can vary about 2-10%, which is similar to the luteal phase variation.

In other words, metabolism might tick up before your period, but that’s not abnormal, and there’s no evidence that the average woman suddenly burns 300 extra calories per day.

What does change more reliably for women is appetite. A 2025 meta-analysis found that women consumed an average of 168 additional calories per day during the luteal phase. But that number varied widely, and the studies relied on self-reported food intake, which is difficult to measure.

The good news is that none of this requires a special diet or calorie calculation. The modest increase in hunger is a normal response to normal physiology, not something you need to fight or “fix.” And that short-term change in hunger and appetite is not enough to create a real, meaningful change to your weight. 

If you’re genuinely hungrier, try to prioritize satisfying foods high in protein and fiber, and include iron-rich foods in your diet. 

Fitness
Is Zone 2 Really the Sweet Spot for Cardio Fitness?

You might have heard fitness influencers rave about Zone 2 training. It's low and slow, and supposedly the magic bullet for boosting your metabolism, mitochondria, and long-term health. 

However, recent research suggests higher-intensity exercise may deliver better results than Zone 2 cardio for most people, especially when time is limited.

The narrative review examined claims about Zone 2 training and its effects on mitochondrial health and cardiorespiratory fitness. The studies suggest that higher-intensity exercise might deliver better results more consistently. This was not necessarily all-out intervals, but simply working above an easy Zone 2 pace, whether through intervals or harder continuous cardio.

The higher intensity places greater demand on your energy systems, triggering more adaptations in your mitochondria. That means greater energy production and better overall cardiovascular health. 

And while Zone 2 cardio can still be great for your health, the pace may not create a strong enough stimulus for most people unless done at very high volumes.

One thing we noticed: the authors found surprisingly few studies that tested Zone 2 exactly as it's popularly defined, so much of the review focused on closely related research rather than head-to-head Zone 2 trials. And many of the claims about Zone 2 cardio come from research on elite endurance athletes, so the average person might not see the same benefits.

If you're pressed for time or want faster results, don't fear higher intensity, even if it’s 1 or 2 times per week, for 10 or 20 minutes. You can still include some lower-intensity work for recovery and variety, but pushing yourself might be the more effective path to long-term health.

The Positive Corner of The Internet
About Arnold’s Pump Club Editorial Standards

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Publisher: Arnold Schwarzenegger​

Editors-in-chief: Adam Bornstein and Daniel Ketchell