Blog

Evidence-based writing on health data, wearables and what the research actually supports.

Forward Head Posture: 10 Habits Backed by Research

Exercise reliably changes craniovertebral angle across 7 RCTs and 627 people. 10 habits the research supports, and what the pain evidence really shows.

24 August 2026 · Hydra Editorial

How to Fix Bad Sleep: 10 Habits With Real Evidence

Across 60,977 people, sleep regularity beat sleep duration as a mortality predictor. 10 sleep habits with real numbers behind them.

24 August 2026 · Hydra Editorial

What Does a Dry Sauna Actually Do? The 20-Year Data

Over 20 years, sudden cardiac death hit 5.0% of frequent sauna users vs 10.1% of weekly users. What the Finnish data shows, and its limits.

24 August 2026 · Hydra Editorial

Why Am I Always Tired? What the Data Says

14% of US adults have iron deficiency and most would never be tested. Three measurable, commonly missed contributors to persistent tiredness.

24 August 2026 · Hydra Editorial

A Morning Routine for Longevity, Built on Three Findings

The brightest tenth of daytime light exposure tracked with 17-34% lower mortality across 88,905 people. A morning routine built on three findings.

24 August 2026 · Hydra Editorial

How to Build an Anti-Aging Lunch: What 105,000 People Ate

Top-quintile diet quality tracked with 86% higher odds of healthy aging at 70 across 105,015 people. What that looks like as an actual lunch.

24 August 2026 · Hydra Editorial

An Evening Routine for Longevity: What the Light Data Shows

Brightest-tenth night light exposure tracked with 21-34% higher mortality across 88,905 people. An evening routine built on the light and meal data.

24 August 2026 · Hydra Editorial

Recovery for 5K and 10K Runners: What the Meta-Analyses Rank

Across 99 studies, massage beat ice baths 5 to 1 for soreness and stretching did nothing. What recovery methods rank for 5K and 10K runners.

24 August 2026 · Hydra Editorial

The Best Exercise to Live Longer, According to 147,374 People

Across 147,374 people over 30 years, combining aerobic and resistance training tracked with 45-58% lower mortality. The dose numbers for each.

24 August 2026 · Hydra Editorial

How to Improve Your HRV: What Actually Moves the Number

Exercise raised RMSSD with a pooled effect size of 0.84 across 16 trials. What moves HRV, what suppresses it, and why your number is not comparable.

24 August 2026 · Hydra Editorial

How to Improve Your Running: Three Levers With Evidence

Strength training improves running economy and polarized training improves VO2peak, but neither does what most runners assume. The evidence, with effect sizes.

24 August 2026 · Hydra Editorial

Ice Plunges: What the Randomized Evidence Actually Shows

A meta-analysis of 11 trials and 3,177 adults found cold plunges cut stress at 12 hours, raised inflammation acutely, and did nothing measurable for immunity.

24 August 2026 · Hydra Editorial

Air Quality and Blood Pressure: How Big Is the Effect?

Ten randomized trials found air purifiers cut systolic blood pressure by about 4 mmHg. The PM2.5-to-blood-pressure evidence, with effect sizes and limits.

24 August 2026 · Hydra Editorial

How to Improve Home Air Quality: What the Measurements Show

Gas stoves raise indoor NO2 by 4.0 ppbv and it reaches the bedroom. Four home air quality interventions ranked by what randomized trials actually measured.

24 August 2026 · Hydra Editorial

Plasticizers and Health: What the Evidence Supports

A global model attributed 356,238 deaths to DEHP exposure in 2018. What the phthalate and BPA evidence supports, and how much is modelled rather than measured.

24 August 2026 · Hydra Editorial

How to Reduce Plasticizers at Home: The Three-Day Experiment

Three days of fresh, unpackaged food cut urinary BPA by 66% and DEHP metabolites by over half in 20 people. What that study tested, and what it did not.

24 August 2026 · Hydra Editorial

Heart Disease Prevention: Which Tests, and When

The 2026 ACC/AHA guideline added lifetime Lp(a) testing and lipid screening from 19. Which tests are recommended, at what age, and why it changed.

24 August 2026 · Hydra Editorial

How Much of GLP-1 Weight Loss Is Muscle?

Across trials, lean mass accounts for anywhere from under 15% to 60% of weight lost on GLP-1 therapies. That spread is the story.

20 August 2026 · Hydra Editorial

Semaglutide's Heart Benefit Did Not Track Weight Loss

In SELECT, 17,604 adults on semaglutide saw fewer cardiac events regardless of how much weight they lost. Why the scale is a poor risk readout.

20 August 2026 · Hydra Editorial