Prof Dean Ho before and after DELTA (2021 vs 2024). Credit: Professor Dean Ho

Continuous tracking of one participant showed how metabolic and physiological health measures can shift substantially over time in response to lifestyle changes.

Most people learn about their health through an annual screening, a single snapshot that can miss what happens during the rest of the year.

Researchers at the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), are exploring a different approach to health and longevity by measuring how the body functions and changes from moment to moment rather than relying only on static markers.

Professor Dean Ho, Director of the Institute for Digital Medicine (WisDM) at NUS Medicine, led the research and also served as its only participant, giving the study an unusually personalized design.

Called DELTA, the study starts from the idea that each person has an individual biological baseline influenced by age, stress, sleep, food, exercise, and illness, and that this baseline can change over time.

To follow those shifts, the researchers varied fasting periods, exercise routines, and nutrition while continuously tracking Prof Ho’s physiological responses. His regimen involved fasting for around 20 hours each day, completing several 48-hour fasts, doing 90 minutes of strength or cardiovascular exercise every morning, and following a structured diet based on leafy greens, seeds, olive oil, lean protein, and other Mediterranean-style foods. Drinks were limited to water, electrolytes, black coffee, and black tea without milk or sugar.

Prof Ho, aged 47, said, “We started this study to better understand what happens between annual health screenings, which most people rely on as their measure of health — to look beyond static markers and focus on how the body functions and changes in real time. We know people are different from each other, but we are also different from ourselves over time. Everyone has their own ‘DELTA’ — a unique, evolving set of data that reflects the fact that health is a story, not a snapshot.”

Real-time tracking captures hidden changes

The research, published in the peer-reviewed journal PLOS One, started in mid August 2024 and remains ongoing. For about eight months, Prof Ho simultaneously wore three devices, Whoop, Garmin, and Apple Watch, giving the researchers a longer record than typical consumer wearable reports provide.

The work follows an earlier 2024 study in PNAS Nexus that tracked his metabolic changes over an extended period. In the latest research, DELTA captured metabolic switching over much shorter intervals, sometimes within minutes, revealing changes in how efficiently metabolism reacts to acute stress that longer-term measurements could miss.

Metabolic switching describes how quickly the body moves between using sugar and fat for energy, with faster switching generally indicating greater metabolic flexibility.

Multiple health measures improved over time

The DELTA regimen resulted in several notable improvements:

• In someone Prof Ho’s age, metabolic switching typically takes 36 to 72 hours or longer and often becomes less efficient with age. His switching time improved over the course of the study, falling from more than 24 hours to 16.5 hours.
• A custom artificial intelligence (AI) copilot developed by the researchers estimated Prof Ho’s biological age at approximately 32, almost 15 years below his chronological age. Conventional biological age estimates generally use a single set of molecular or physiological measurements to provide a static picture of health and disease risk at one point in time. Such measurements reveal less about how effectively the body responds to and recovers from stress, an important feature of healthy aging. The AI-powered healthspan copilot instead tracks molecular and physiological reactions to stress in real time to assess biological resilience, including the speed at which the body adapts and recovers.
• Prof Ho’s resting heart rate declined from 65 beats per minute (bpm) to 46 bpm, a change that can indicate more efficient heart function and improved recovery.
• His sleep pattern also changed. Bedtime moved from after midnight to around 9pm, total sleep increased from approximately 5 hours to nearly 8 hours, deep sleep increased, and time spent awake during the night decreased.
• Measures of the gut microbiome also changed positively, with no detectable Fusobacterium in any measurement and signs of improved energy conservation during certain fasting periods.

The goal is personalized health guidance

Prof Ho and his colleagues hope DELTA can help people interpret their own health information and use it to make informed lifestyle decisions rather than relying on generic routines or pursuing a single ideal that is supposed to suit everyone. Many existing approaches to longevity, ranging from conventional drug development to biological age clocks, continue to depend on static measurements taken at particular moments. Even systems that use AI often combine data collected periodically rather than continuously measuring how the body functions, responds, and adapts.

“DELTA represents a shift toward function-based longevity science by measuring physiological resilience instead of relying on static snapshots. We hope this work will not only help redefine how healthy aging is understood, but also showcase Singapore’s growing role in pioneering the future of personalized longevity research,” added Prof Ho.

Reference: “DELTA: Strengthening human biological resilience with an N=1 digital health and dynamic biomarker protocol” by Peter Wang, Nigel Foo, Chengxun Su, Nicole Yong Ting Leung, Shang Wei Song, Gyula Seres, Yoann Sapanel, Lissa Hooi, Avelle Wong, Yoong Hun Ong, Poonam Rai, Hyunjin Park, Han Shi Jocelyn Chew, Laureen Yi Ting Wang, Jonathan Wei Jie Lee, Xavier Tadeo and Dean Ho, 12 August 2026, PLOS ONE.
DOI: 10.1371/journal.pone.0354234

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