Why do we sweat? And what secrets does it hold about our bodies? On this week’s podcast, Professor Luke O'Neill dives into the fascinating science of sweat. From keeping our body temperature in check to signalling stress and even potential mate selection, sweat is far more than just water and salt.

The podcast explores how sweat is made by specialized eccrine glands, originating from plasma in our blood, and why humans are among the sweatiest animals on the planet. Luke explains how the average adult can produce up to four litres a day, and why staying hydrated is crucial.

But there’s more: stress, exercise, and climate all change how and why we sweat. Sweat itself is odorless, but bacteria, lactic acid, and urea can create the smells we associate with adolescence, gyms, and armpits. And surprisingly, sweat contains proteins that fight bacteria, hinting at a role in our body’s natural defence.

Could sweat one day be a diagnostic tool for disease? Why do identical twins sweat the same amount? And could it even act as a pheromone signal? Professor O’Neill explains all this and more, in a conversation sparked by a listener question from Siún.

If you want to ask Luke your own science question, email him at:

📧 laoneill@tcd.ie

Weather forecasts are famously imperfect, but the science behind them is far cleverer than we usually give it credit for.

In this week's podcast, Professor Luke O’Neill explores how weather forecasting works, and why floods remain one of the hardest things to predict. Luke isn’t a meteorologist — although he did briefly consider it in college — but too much physics put him off. Still, he’s an ideal guide to the basics because the weather is really about a few core ideas behaving badly.

At its heart, forecasting comes down to temperature, air pressure, humidity, sunlight, and the way air flows like a fluid. Air moves from high to low pressure, dragging wind and weather systems with it. Add water vapour into the mix and things get interesting very quickly.

People have been trying to predict the weather for hundreds of years, using almanacs, folklore, and observation. It was never perfect, but it mattered hugely to farmers and sailors. Rain, in particular, remains tricky. Moist air rises, cools and condenses into clouds — but rain doesn’t just appear. It needs tiny particles like dust, sea salt, or pollen to form droplets, and those microscopic details are hard to pin down.

Today’s forecasts rely on satellites, radar, weather balloons, and ground stations, all feeding data into powerful computer models. Those models keep improving, and artificial intelligence is now helping to sharpen predictions.

Flooding is even more complicated. It’s not just about how much rain falls, but how fast it falls, how long it lasts, and where it lands. Soil type, vegetation, evaporation, and urban concrete all matter. Forests and wetlands act like sponges, while cities can make flooding worse — something Ireland knows well after decades of building on flood plains.

Some countries lead the world in flood modelling, but nowhere reliably predicts flash floods. Luke argues that weather is a brilliant way to teach science, and that we already know how to reduce flood risk. The challenge now is acting on that knowledge and getting on with it.

Why does the marathon push the human body to its absolute limits? And why do some people seem built to keep going when everyone else hits the wall? On this week’s podcast, Professor Luke O’Neill takes a biochemical deep dive into marathon running, sparked by a listener’s request. The modern marathon may trace its roots back to Ancient Greece, but what happens inside the body during those 26.2 miles is a very modern scientific story — one that turns runners into walking, sweating demonstrations of bioenergetics.

Luke explains how the body powers long-distance running by converting energy rather than creating it, moving between carbohydrates and fats to keep muscles firing. ATP — the energy currency of life — sits at the heart of the process, with phosphocreatine, glycolysis and oxygen all playing starring roles. When carbohydrate stores finally run dry, runners hit the infamous “wall”, a moment when the body is forced to switch fuel sources, and everything suddenly feels much harder.

The podcast also looks at how training physically reshapes marathon runners over time: denser networks of capillaries in muscles, powerful hearts with remarkably low resting heart rates, and lungs capable of shifting huge volumes of oxygen. Luke explores why elite runners can seemingly run a marathon at will.

There’s science behind the mental side too. Endorphins and the so-called “runners high” can lift mood for days, while visualisation plays a key role in endurance. Luke even dips into the Guinness Book of World Records to uncover astonishing marathon facts, including runners in their 90s and some jaw-dropping physiological extremes.

Along the way, Luke admits he’s never run a marathon himself — but from a biochemist’s point of view, few sports are more revealing of how the human body really works.

You can suggest future topics by emailing Luke at laoneill@tcd.ie.

Turmeric is everywhere – in teas, capsules, curry powders and health ads – but what does it actually do? On this week's podcast, Professor Luke O’Neill explores the science behind the golden root, explaining why it’s been used for centuries in Eastern medicine and what modern research tells us about its effects.

We dive into curcumin, turmeric’s active ingredient, and learn how it fights inflammation, works as an antioxidant, and even interacts with our gut bacteria to become more potent. Luke separates the science from the hype, highlights the evidence for conditions like ulcerative colitis, and explains why taking turmeric might help – as long as it’s not replacing your prescribed medication.

Along the way, we uncover fascinating trivia: the plant’s own sunscreen, why it stains everything yellow, and how it became a sacred dye for Buddhist and Hindu robes. Whether you love it in your curry or in your supplement cabinet, this episode shows why turmeric has earned its golden reputation.

This week on the podcast, Professor Luke O’Neill turns his attention to a condition that’s often misunderstood and far more common than many people realise: Lewy Body Dementia.

Requested by listener Eben Stewart ahead of World Lewy Body Dementia Day on January 28th, the episode looks at what causes LBD, how it differs from Alzheimer’s and Parkinson’s, and why so many people are living with it without a diagnosis. Around 10,000 people in Ireland are believed to have Lewy Body Dementia, yet only a fraction are formally on the register — a gap that has real consequences for care, treatment, and awareness.

Luke explains how abnormal protein clumps, known as Lewy bodies, build up in nerve cells and trigger inflammation and neurodegeneration. LBD affects both cortical and sub-cortical regions of the brain. That helps explain why early symptoms are often cognitive rather than physical — confusion, memory problems, difficulty with decision-making, and, in many cases, vivid visual hallucinations and delusions.

As the condition progresses, Parkinson’s-like symptoms such as tremor and rigidity usually emerge too. Treatment is complex and requires care, with some anti-psychotic medications risking a worsening of symptoms, while drugs like L-Dopa can help manage movement issues. Luke also talks about ongoing research, including work happening in his own lab on potential new treatments now in clinical trials.

The episode also touches on why Lewy Body Dementia is more common in men, why it typically appears after the age of 50, and the role family history can play. And it reflects on the stories of well-known figures who lived with Parkinson’s and LBD, including Robin Williams, Glen Campbell and Michael J Fox, whose experiences helped shine a light on just how challenging — and misunderstood — LBD can be.

Trinity College Dublin will host a Lewy Body Dementia awareness event on January 28th in Unit 18 on the Pearse Street campus from 12pm, as part of efforts to improve understanding and recognition of the condition.

Why do some people love wine, while others can’t stand it? Why did Covid strip food of its pleasure for so many? And how much of what we call “taste” is really happening in the nose, the brain, and even our memories?

This week's podcast takes on a listener-requested topic: the science of taste and flavour. Professor Luke O’Neill explains why taste is far more complex than the tongue alone, with up to 80% of flavour driven by smell and only around 20% by taste itself. He walks through the five core tastes — sweet, sour, salty, bitter and umami — and explains how specialised receptors in the tongue, nose, throat and even the stomach detect chemicals in food. These discoveries were so fundamental they led to Nobel Prizes.

The episode also explores how nerves shape flavour: why chilli feels hot, mint feels cool, and fizzy drinks tingle. Texture matters too. Creaminess, crispiness, and mouthfeel all shape how food is experienced. Vision and psychology play their part as well, from expectation bias to the power of nostalgia, famously captured by Proust’s madeleine.

Genetics turn out to be crucial. Some people find coriander tastes like soap; others find it fresh and citrusy. Some recoil from sprouts, broccoli, chilli or umami-rich foods, while others seek them out. Finally, Luke looks at how chefs have been quietly mastering this science for centuries, using fat to enhance flavour, stacking umami to build intensity, and manipulating texture and aroma to transform how food tastes.

This episode was prompted by listener requests from Stephen and Eoin. If there’s a science topic you’d like Luke to tackle next, you can email laoneill@tcd.ie.

Ireland, like much of Europe, is in the middle of a serious flu outbreak. This week’s podcast focuses on why this year’s influenza wave is hitting so hard, who is most at risk, and what actually helps.

Professor Luke O’Neill explains why flu thrives in winter, spreading easily indoors where ventilation is poor. He outlines the classic flu symptoms — high temperature, severe fatigue, aches and pains, cough and runny nose — and why this strain is leaving many people bedridden for days rather than just mildly unwell. Flu is currently a bigger problem than Covid — widespread immunity has made Covid more benign, while influenza continues to evolve, throwing up new variants every winter.

The episode looks at who needs to be especially careful, and why flu season is such a concern for hospitals, with emergency departments under pressure and trolley numbers rising. Luke also discusses why this year’s vaccine has been less well matched than usual, after the virus mutated on its way from the southern to the northern hemisphere — and why it still matters.

And if flu symptoms do strike, Luke’s advice is simple: rest, stay hydrated, manage fever and pain, and don’t panic.

Every January, millions of us promise that this will be the year we finally change our habits. We’ll sleep more, stress less, move our bodies, eat better, learn something new, or finally tackle the clutter that’s been quietly judging us from the corner of the room. But by spring, most of those resolutions are long forgotten.

On this week’s podcast, Professor Luke O’Neill digs into what research really tells us about New Year resolutions — why we make them, why so many fail, and how we can dramatically improve our chances of sticking with them.

Luke explains why the pandemic triggered a surge in resolution-making, how the brain responds to fresh starts, and why January gym memberships soar even as long-term attendance collapses. He also shares evidence-based strategies that actually work, from setting specific and measurable goals to harnessing social support, using apps, and learning new skills that boost brain health as well as motivation.

This isn’t about willpower or guilt. It’s about understanding how humans change — slowly, imperfectly, and with the right conditions. If you’re setting intentions for the year ahead, this is the science you want on your side.

You can email Luke with questions or suggestions for future episodes at laoneill@tcd.ie.