Cardio vs Weights, Male Fertility, NMN vs NR

Lift before cardio for more fat loss, sperm health predicts longevity, and should you take NMN or NR? Plus: the 4-minute fix for “nerd neck” that saves your spine (and your breathing).

Author

Tash Jamieson
June 20, 2025

Good morning 👋 Welcome to the Superpower +Signals, where we share 3 of the weeks top health finds, 1 life-changing health hack and 1 number.

As we settle into the Fathers Day weekend, evidence shows that having kids might be beneficial to the health of men - especially if you’re a girl-dad1.

Cardio before or after weights?

New research has cracked a long-running gym debate: lifting weights first leads to greater fat loss, especially visceral fat (that’s the nasty stuff linked to heart disease2. Why? Strength training drains muscle glycogen (the stored form of glucose), forcing your body to burn more fat during cardio afterward.

Our take: Want fat loss or bigger muscles? Lift first, run second. One meta analysis found that strength gains are significantly higher when resistance training comes before cardio3. Chasing a better VO₂ max or endurance? Flip it, cardio first. But honestly, if it's general health and longevity you’re after, forget the details. Just show up consistently and do both4.

Is male-fertility tanking?

Just days before fathers day, Dr Gabrielle Lyon chatted with male-fertility expert Dr. Larry Lipshultz on her podcast episode Why Men’s Fertility Is Declining5. Yes, male-fertility is declining globally. Oxidative stress (too many free radicals and not enough antioxidants) seems to be the culprit. No, ED and fertility often have no correlation (ED is normally a blood-flow issue, not a hormonal or endocrine one!)

Our take: Even if you never plan on having kids, fertility and semen quality is still a great proxy for overall health, so worth taking seriously. In one 2025 study that followed 78 284 over 50 years, men with healthier sperm counts (>120 million motile sperm) lived roughly 2.7 years longer than men with lower counts (0–5 million)6.

Should you be taking NMN or NR?

Our take: NMN and NR are supplements designed to crank up NAD+, which is your cells' built-in repair and energy boost. Slightly different structure, same core mission: boost NAD+, slow aging, feel better. Even if the jury is still out on taking NMN or NR for longevity, NMN does seem to show immediate benefits, like better sleep, better endurance, insulin sensitivity… the list goes on7.

Superpower Member Hack: Fixing ‘nerd neck‘.

Ajay (30M, Sydney) fixed his Forward Head Posture (FHP) aka ‘nerd neck’ or ‘text neck’ through strengthening exercises, rather than just the classic advice of sitting up straight. Here’s a simple, 4 min set you can do8.

Fixing FHP is way more important than just having good posture; FHP is associated with reduced respiratory function9, worse balance10 and increased mortality rates11.

One number:

Optimal fasting blood glucose level.

That’s all for this week 🫡

If you see something interesting or cool in health / longevity news, please send my way!

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