How this content gets made — and what it isn't.

Who publishes this site

Helixspan is published by Healthworks, an independent project interested in healthspan — the number of years people live in good health rather than simply the number of years they live. Healthworks is small and self-funded. It is not a clinic, a medical practice, a research institution, or a commercial health company, and it does not employ physicians or clinical researchers.

We say that plainly because it matters for how you should read everything else here. Our work is summary and synthesis of published research, not original research and not clinical expertise. Where we describe a finding, we are describing what a study reported — not offering a professional judgment about what you personally should do.

What we publish

Two things, and only two:

1. The calculator. A transparent model that maps seven modifiable lifestyle factors onto an estimated healthspan and a 0–100 composite score. Every weight the model uses is published on the methodology section of the homepage. Nothing is hidden or proprietary.
2. The guides. Explanatory articles in the Learn section that unpack the research behind each factor: what the studies actually measured, how strong the evidence is, and where the honest uncertainty lies.

How we source claims

Our sourcing rules, in order of preference:

• Meta-analyses and systematic reviews over individual studies, because single cohorts are noisy and prone to reversal.
• Large prospective cohorts and randomised trials over cross-sectional or retrospective data.
• Named, checkable citations. Every quantitative claim in a guide traces to a source listed at the foot of that guide, with author, journal, and year, so you can go read it yourself.
• Institutional statistics — WHO, the Global Burden of Disease project — for population baselines rather than our own extrapolations.

We prefer sources that are open-access wherever an equivalent paywalled source exists, because a citation you can't read is close to no citation at all.

What we deliberately don't do

This list is as important as the one above.

• No medical review claims. Our guides are not reviewed by a doctor, and we never imply otherwise. Where the content carries a "not medically reviewed" label, that label is accurate.
• No invented credentials. We do not list fictional authors, advisory boards, or expert reviewers. If a name or qualification appears on this site, it is real.
• No supplements, protocols, or products. We do not sell anything, and we do not recommend branded products, supplements, tests, or programmes.
• No precision we don't have. The calculator's outputs are population-level estimates with wide uncertainty. We resist presenting them as personal predictions, and we say so on the result itself.
• No fear-based framing. Healthspan content trends easily toward alarm or toward miracle-cure optimism. We aim for neither.

How the calculator's numbers work

The model anchors on WHO Healthy Life Expectancy figures for high-income populations, then applies additive year modifiers for each of the seven factors, then rescales the result into a 0–100 score centred at 72. Because the modifiers are additive and independent, the model cannot capture interactions between factors — in reality, poor sleep and poor diet are not independent, and their combined effect is not necessarily the sum of their separate effects.

The plausible total range across all seven factors is roughly −25 to +12 years. That range is consistent with the lifestyle-attributable spread reported in large cohort studies, but it is a modelled range, not a measured one. Two people with identical inputs can have very different real outcomes, because genetics, medication, access to care, environmental exposure, injury, and luck are all outside the model.

Corrections

If you find an error — a misread study, a number that doesn't match its source, a claim stated more strongly than the evidence supports — tell us via the contact page. We will correct it and note the change with a date on the affected page. We would rather be corrected than be confidently wrong.

Funding and independence

The site is funded by display advertising, which is why you may see ad slots on some pages. Advertisers have no input into what we write, no advance sight of it, and no ability to have content changed or removed. We do not run sponsored posts, affiliate links, or paid placements, and we do not accept payment to mention a product.

The bottom line on trust

Use this site the way you'd use a well-referenced encyclopaedia article: a decent orientation, a set of citations worth following, and a starting point for a conversation with an actual clinician. Not a diagnosis, and not a substitute for one. If something here contradicts advice from your doctor, your doctor knows your situation and we don't.