Day-to-day variables can also affect results. Sleep, nutrition, hydration, recovery, and even equipment can influence how well someone performs on test day. "The thing about endurance sports is that what you put in is what you get out," says McQuality. In lab testing, his team found that carbon-plated running shoes slightly improve VO2-related performance by increasing efficiency, allowing runners to sustain higher workloads before fatigue sets in. Taken together, these factors help explain why VO2 max is best viewed as a context-dependent snapshot, not a fixed measure of physical fitness. It's most useful when tracked over time, under similar conditions, and alongside other markers of performance and health.

Several studies being presented at the American College of Cardiology's 67th Annual Scientific Session demonstrate how the computer science technique known as machine learning can be used to accurately predict clinical outcomes in patients with known or potential heart problems. Collectively, the findings suggest that machine learning may usher in a new era in digital health care tools capable of enhancing health care delivery by aiding routine processes and helping physicians assess patients' risk. While clinical scoring systems and algorithms have long been used in medical practice, there has been a marked uptick in the application of machine learning to improve such tools in recent years. In contrast to traditional algorithms that require all calculations to be pre-programmed, machine learning algorithms deduce the optimal set of calculations by looking for patterns in large collections of patient data. The new studies presented at ACC.18 demonstrate how machine learning can be used to predict outcomes such as diagnosis, death or hospital readmission; improve upon standard risk assessment tools; elucidate factors that contribute to disease progression; or to advance personalized medicine by predicting a patient's response to treatment.

FRANKFURT (Reuters) - Nearly a decade after the iPhone broke the mould for mobile phones the question is now being asked whether the evolution of the smartphone has finally come to an end as even Apple now treats older, smaller 4-inch screens as something new. Industry experts believe innovation in smartphones is giving way to phone functions popping up as software or services in all manner of new devices from cars to fridges to watches and jewellery rather than remaining with handheld devices. And analysts and product designers said fresh breakthroughs are running up against the practical limits of what's possible in current smartphone hardware in terms of screen size, battery life and network capacity. "Everything in the phone industry now is incremental: slightly faster, slightly bigger, slightly more storage or better resolution," said Christian Lindholm, inventor of the easy text-messaging keyboards in old Nokia phones that made them the best-selling mobile devices of all time. The financial stakes are high as the futures of Apple, Google, and Microsoft, the world's three biggest listed companies at the end of last year, may turn on who gets the jump on making handsets redundant.