Between Saturdays

This week: What your blood can tell you three decades ahead, how exercise can rewind your heart’s age, the hidden cost of too much sitting, and a pacemaker that vanishes.

This week, five studies reminded us that heart health isn’t something we “get to later” — it’s something shaped silently and steadily by what we do now. From a landmark study showing how three simple blood markers can forecast heart events decades in advance, to research revealing the specific sitting-time threshold where risk spikes, the message is clear: what protects or weakens the heart often happens long before symptoms ever appear.

Add to that a dissolvable pacemaker the size of a grain of rice, and compelling data on how a two-year exercise program can effectively reverse heart aging — and what emerges is both urgency and agency. Our daily habits, our early screenings, even our stillness — they’re all part of the long game.

As always, this roundup skips the noise and goes straight to what matters — research-backed insights that help us live, parent, and function with more clarity, and a little more care.

Caught My Eye…

• Too Much Sitting and the Surprising Heart Risk Threshold

  For anyone trying to check the “healthy” box with a few workouts a week, a new study out of the Journal of the American College of Cardiology offers a reality check: even if you’re exercising regularly, sitting too much may still quietly raise your risk of heart failure and cardiovascular death.

  Researchers looked at data from nearly 90,000 participants in the UK Biobank, most in their early sixties, and used wrist-worn accelerometers to track how long people were sedentary each day — meaning time spent sitting, reclining, or lying down while awake. They followed participants for an average of eight years.

  The average person sat for about 9.4 hours a day. But once sedentary time crossed 10.6 hours daily, the risk curve took a sharp turn:

  • Risk of developing heart failure increased by 40%

  • Risk of dying from cardiovascular causes increased by 54%

  Interestingly, the risk remained relatively flat until that 10.6-hour mark — then rose significantly beyond it. What’s more, even meeting the standard guideline of 150 minutes of moderate-to-vigorous activity per week didn’t fully offset the damage of long sedentary stretches.

  Cardiologist Dr. Shaan Khurshid, co-author of the study, emphasized the need to treat sitting time as its own independent risk factor. And in an accompanying editorial, Dr. Charles Eaton pointed out that just 30 minutes less sitting a day — even light activity — lowered heart failure risk by 6%.

  If that sounds like a call to arms for standing desks and walking meetings, it is. But the takeaway isn’t about reinventing your lifestyle — it’s about small, repeatable nudges:

  • Try to keep sedentary time under 10.6 hours per day

  • Stand, stretch, or walk for a few minutes each hour

  • Rethink stretches of stillness in your workday, commute, or leisure time

  We tend to focus on what kind of activity we’re getting — but how long we go without any may be just as important.

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• A Pacemaker That Dissolves — No Surgery Required
  In a striking example of bioengineering meeting bedside need, researchers at Northwestern have created a fully dissolvable, battery-free, wireless pacemaker — roughly the size of a grain of rice. It’s injected into the body and disappears when it’s no longer needed.

  This is temporary cardiac pacing, reimagined — especially for infants or patients recovering from surgery, where complications from wires and removals carry significant risk.

  Key features:

  • Injectable: No surgical implantation needed

  • Wireless and battery-free: Powered by body fluids via a galvanic reaction

  • Externally controlled: A wearable chest patch monitors heart activity and activates the device using near-infrared light

  • Bioresorbable: Made of materials like magnesium and tungsten that safely dissolve within 5–7 weeks

  Why it matters:
  Traditional temporary pacemakers require follow-up procedures for removal, often involving surgical risk. This dissolvable device reduces patient burden while offering precise, temporary support. It's especially promising for:

  • Infants with congenital heart defects

  • Adults recovering from cardiac surgery

  Human trials are next. Long term, researchers hope this platform can extend to other therapeutic areas — including nerve regeneration and wound healing.

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• A Blood Test That Sees 30 Years Into the Future
  A landmark study in The New England Journal of Medicine has shown that three common blood biomarkers can predict a woman’s long-term risk of heart attack, stroke, or cardiovascular-related death — up to 30 years in advance.

  Researchers from Brigham and Women’s Hospital followed nearly 28,000 initially healthy U.S. women for three decades. They found that elevated levels of three markers at baseline significantly increased the risk of major cardiovascular events, often long before any symptoms emerged.

  The markers:

  • hsCRP (high-sensitivity C-reactive protein) — a sign of inflammation

  • Low-density lipoprotein cholesterol (LDL-C): Commonly known as “bad” cholesterol.

  • Lipoprotein(a), or Lp(a): A genetically influenced lipid not included in standard panels.

  Women with the highest levels of each showed:

  • Women with the highest hsCRP levels had a 70% greater risk of cardiovascular events.

  • High LDL-C was associated with a 36% increased risk.

  • Elevated Lp(a) carried a 33% higher risk.

  But when all three were elevated?
  → Risk of a major cardiovascular event increased by 2.6x
  → Risk of stroke jumped by 3.7x

  Notably, while LDL-C is modifiable via lifestyle or statins, and hsCRP can respond to diet, exercise, sleep, and stress, Lp(a) is largely genetic — though therapies targeting it are in clinical development.

  Why it matters:
  Cardiovascular screening often starts too late and too narrowly. This study suggests broader early testing — particularly for women in their 30s and 40s — could allow for interventions long before symptoms arise.

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• The 20-Year Heart Rewind

  We all know exercise is good for the heart — but a study published in Circulation shows that the right kind of exercise, started early enough, can actually reverse heart aging by up to 20 years.

  The two-year randomized trial, led by Dr. Benjamin Levine, followed 53 sedentary adults aged 45–64 for two years. Participants were assigned to either light flexibility training or a more intense aerobic and resistance regimen. Those in the structured exercise group experienced significant improvements in cardiac elasticity, oxygen uptake, and overall cardiovascular function.

  The exercise group followed what researchers called the "Prescription for Life":

  • 4–5 days per week of aerobic exercise

  • 1 session of HIIT per week (4x4 method: 4 mins at ~95% HR, 3 mins recovery)

  • 30+ minute sessions

  • A mix of moderate cardio, HIIT, and resistance training

  Outcomes:

  • Increased VO₂ max (a marker of aerobic fitness)

  • Reduced left ventricular stiffness

  • Improved blood flow and heart responsiveness — consistent with a cardiac profile 15–20 years younger

    In short: a heart that functioned like it was two decades younger.

  The heart appears most “trainable” before age 65, when muscle elasticity is still responsive. Benefits are still observed when starting later, but the reversal of aging is more modest.

Detailed Readings

Sitting Too Long Can Harm Heart Health, Even for Active People

New blood test could predict heart disease risk 30 years ahead of time: groundbreaking study

How Exercise Prevents & Reverses Heart Aging

World’s smallest pacemaker’ is implanted with a syringe and dissolves when it’s no longer needed