Dr Xand and Chris van Tulleken share their anti-ageing secrets

From how putting down your phone can relieve stress to beating high blood pressure by eating beetroot… TV twin doctors Dr Xand and Chris van Tulleken share their anti-ageing secrets

  • Chronic stress has been linked to weight gain, depression and heart disease
  • It reduces the effectiveness of our immune system and may even harm our DNA
  • Twin doctors Dr Xand and Chris van Tulleken on how to de-stress to live longer

Far too many of us are addicted to our phones. Xand spent 15 hours on his phone last week and more than four hours on Twitter alone, which feels like too much, though he insists it is mostly in the bathroom or waiting in a queue.

There’s evidence that smartphones can cause stress, exacerbate depression and disrupt sleep — all bad news for our healthspan — but some research suggests that they might also be making you less intelligent, simply by being close at hand.

The theory is that this is down to distraction. Most people check their phones more than 80 times a day, but because we all have a limited amount of attention, the mental effort of trying to ignore our phones might cause us to run out of brain space.

We put this theory to the test for The Twinstitute. For our experiment we split our 30 pairs of twins into two groups to take an identical IQ test. 

There’s evidence that smartphones can cause stress, exacerbate depression and disrupt sleep

The only difference was that half our twins had their phones taken away, while the others were allowed to keep them on their desks (switched off).

The results were astounding — the twins whose phones were removed scored 5 per cent higher than those who had phones in front of them.

This corroborates a 2017 study by the University of Texas, where 800 smartphone users were asked to sit tests geared to measure the brain’s ability to hold and process data. 

The people who were told to leave their phone in another room consistently outperformed those who left their phone on their desk.

Even if you think you’re giving a task or a person your full attention and focus, if you can see your phone, there’s every chance you’re not.

The Texas study showed that it doesn’t matter whether your phone is turned on or off. Simply having it within easy reach reduces your ability to perform tasks because part of your brain will be preoccupied by the effort of not picking it up.


  • Avoid your phone for the first hour of every day. This may mean getting an old-fashioned alarm clock and charging your phone in a different room — definitely not by your bed.
  • Turn off all notifications so you’re not distracted by bleeps and flashes, and put your phone in a pocket or bag out of sight — check it at set times instead.
  • You probably use your phone more than you realise, so check how much ‘screen time’ you’ve had each day (it’s in the Settings app on an iPhone) and aim to reduce it.
  • Establish a ‘no phones at the table’ rule.

We ourselves do all of the above. Putting your phone in your bag is useful; it’s harder for men but Xand keeps his in his man bag (Timothy Everest, if you’re interested) and says it’s invaluable.

What to eat to beet damaging high blood pressure

Stress can cause blood pressure to spike temporarily and high blood pressure is a major risk factor for heart disease — one of the biggest killers in the Western world.

Heart disease can also lead to heart failure, reducing your quality of life through breathlessness and fatigue.

Although there’s no proof that stress by itself causes long-term high blood pressure, how we cope — or don’t cope — with stress is important, with smoking, drinking, bad diet and broken sleep all pushing up blood pressure and increasing the risk of heart attack and stroke.

Although we’re both sceptical about the idea of ‘superfoods’, studies show that some vegetables contain powerful plant compounds that can play a beneficial role in our body

Being physically active is one of the most important things you can do to prevent or control high blood pressure. It’s also important to eat a healthy diet with plenty of fresh fruit and vegetables, not to have too much alcohol or salt, to stop smoking and drink no more than four cups of coffee per day.

But can some foods help lower blood pressure? Although we’re both sceptical about the idea of ‘superfoods’, studies show that some vegetables contain powerful plant compounds that can play a beneficial role in our body. 

Getting the most out of your veg 

  • Eat salad and vegetables raw. Nitrate levels in them can be reduced by processing and cooking. They are also water-soluble so can be lost in cooking water. Pickling reduces the amount of nitrates in beetroot as they’re lost in the vinegar.
  • Roast beetroot instead of boiling it. If you do boil it, don’t top or tail it before putting it into the water. This will mean that less of the nitrates escape.
  • Steam spinach and other vegetables rather than boiling or use the leftover cooking water in soups and stews.
  • Try beetroot juice, as it retains most of the beetroot (and nitrates) in its raw state.

Chris took part in an experiment with Dr Andy Webb of King’s College London for the BBC2 show Trust Me, I’m A Doctor, to see if eating beetroot, garlic and watermelon — foods that contain compounds that help dilate blood vessels — could help reduce blood pressure.

In garlic, one of the main active ingredients is a compound called allicin, which is released when you chop or crush it. Allicin is thought to act on our kidneys, changing levels of hormones and causing the blood vessels to dilate.

In beetroot, the active ingredient is nitrate — present in both the leaves and the root. When we eat beetroot, our bodies convert this into nitric oxide, which causes the blood vessels to dilate — lowering blood pressure.

The active ingredient in watermelon is called L-citrulline. It seems to work by increasing levels of nitric oxide. For the experiment, 28 volunteers with high blood pressure were divided into three groups: one group ate two cloves of garlic every day, another group ate two large slices of watermelon and the third group ate two whole beetroot.

The results showed that watermelon and garlic didn’t make a difference — but the beetroot did.

In fact, studies on the links between high blood pressure and heart disease suggest that if the drop in blood pressure seen in the experiment was maintained, this roughly translates into a reduction of the risk of stroke and heart attack by 10 per cent!

Of course, beetroot on its own isn’t going to bankrupt the big drug companies. However, it does fit into a toolbox of lifestyle changes that could do just that.

If you can’t stand beetroot, you’ll also find useful amounts of nitrates in green vegetables such as celery, lettuce, watercress, rocket, spinach, chard and broccoli.

Laugh your way to a longer life 

A good belly laugh has been shown to spark production of the ‘feel-good’ brain chemical dopamine and cut production of the stress hormone cortisol.

It also seems to foster the production of calming gamma waves, which are the type of brain waves seen in experienced meditators. 

A good belly laugh has been shown to spark production of the ‘feel-good’ brain chemical dopamine and cut production of the stress hormone cortisol

Even the mere anticipation of a good laugh can boost levels of mood-lifting compounds called endorphins.

Watching a side-splitting comedy can also help with weight loss. At The Twinstitute we asked sets of twins to watch a horror movie or a comedy. 

Our experiment showed that the latter can increase your resting metabolic rate so much — by up to 40 per cent — that you burn more calories. It also gives your abdominal muscles a workout.

However, a horror movie causes you to release adrenaline, which increases your heart rate, and while it might raise your metabolic rate — by 10 per cent — it could also exacerbate harmful levels of stress hormones.

So if you’ve already got enough pressure in your life, choose to watch the comedy instead.

Find a friend

Friendship, and all the activities that come with it, is one of the best stress-busters. Studies show good friendship triggers the release of endorphins — morphine-like brain chemicals that give us a feeling of satisfaction or bliss and boost the immune system.

Robin Dunbar, an evolutionary psychologist at the University of Oxford, explains: ‘Touch, laughter, singing, story-telling, the rituals of religion, eating and drinking socially all trigger the endorphin system, in turn increasing our resistance to disease.’

Want to live healthier for longer? You can with our brilliant series by TV’s twin doctors…

Stress has become a buzzword to describe many aspects of modern life: the difficulties we encounter (‘there’s a lot of stress at work and at home’), and our responses to those difficulties (‘I’m feeling stressed and it’s getting me down’).

It’s such a catch-all idea that it’s easy to dismiss stress as mumbo-jumbo. After all, in many ways life is easier than ever: we’re living longer with a huge range of technologies to improve our lives.

But few things affect our health and our lifespan more than stress. Chronic stress is linked to weight gain, depression and heart disease. It reduces the effectiveness of our immune system (including how well our bodies respond to vaccines) and may even harm our DNA.

Stress has become a buzzword to describe many aspects of modern life: the difficulties we encounter (pictured, Alexander and Christoffer van Tulleken)

In fact, stress is right up there with poor diet and lack of exercise for its damaging effects, and if we want to continue to live healthily well into old age, it is important to try to reduce the impact on our bodies of the stressful world that surrounds all of us.

Over the years we’ve investigated the causes and treatments of stress, what helps and what doesn’t. 

More recently, this includes as part of our BBC2 series, The Twinstitute — where we used ourselves, and 30 sets of identical twins, as human guinea-pigs to take advantage of our matching DNA in order to investigate a range of popular theories about health and wellbeing.

Today, in the final part of our anti-ageing series, we show you ways that have been proven to help make a difference to stress, so you can live well for longer.


In scientific terms, stress is anything that threatens the body and provokes a reaction to cope with the threat. Jumping into cold water; going for a run; spending time in the hot sun; coping with a job interview: these are all ‘stresses’ and they all provoke significant physical changes in our bodies.

First there is a rapid release of adrenaline, which raises our heart and breathing rates and blood pressure, and diverts blood towards our muscles.

Then our bodies release glucocorticoid hormones, the most important and well known of which is cortisol. Cortisol releases more sugar into our bloodstream, regulates our immune system through chemicals called cytokines, and affects our levels of alertness. All of these reactions work to keep us alive and functioning, and are not necessarily harmful.

Did you know…  

Chronic stress can lead to weight gain. 

The stress hormone cortisol is involved in metabolism and fat storage, so it can drive us to pile on pounds when the going gets tough. 

Research from University College London has shown that people with higher levels of cortisol are likely to be heavier and to be overweight for longer. 

But when you can’t escape the constant stresses throughout your day, you can find yourself in a permanent state of chronic stress. That’s bad news for your wellbeing — and your ability to live well for longer. Over recent years certain kinds of stress have been found to be extremely medically significant. Essentially, they seem to arise from people being unable to control important aspects of their lives for long periods of time.

Divorce, a hostile workplace or social environment, loneliness, a low-ranking job and long-term illness all limit people’s control over things that are important to them. The responses that occur as a result are significant.

If you’re a high-ranking Buddhist monk you can probably stop reading here, but everyone else should give it some thought — because almost all of us will experience periods when we find a lack of control over some aspect of our lives stressful, and we’d almost all benefit from trying to alter and reduce our responses to stressful events.

The most important evidence that stress can affect us physically comes from the Whitehall Studies — launched in 1967 and which are still ongoing. These collect and analyse data from British civil servants. They found higher death rates from all causes — and a particularly high risk of death from coronary heart disease — for men who were lower-ranked within the civil service.

This higher risk could not be explained by typical risk factors such as obesity, smoking, physical activity or blood pressure. It’s been calculated that people who have high work demands and low control over them can experience up to a 68 per cent greater risk of premature death.

If you recognise this description of your career (and almost all of us are likely to, in one way) this doesn’t mean you should quit your job or abandon your family. But it is worth taking seriously. Even if you can’t change your environment, you may at least be able to change your reaction to it.


Chronic stress can lead to a breakdown of the mechanisms that keep your stress hormones in balance, and permanently raised levels of stress hormones and cytokines can cause serious problems everywhere. The walls of the heart and blood vessels can thicken due to elevated blood pressure, which can play a role in cardiovascular disease.

Cytokines lead to a permanent state of inflammation, which is increasingly recognised as what makes stress so harmful. Chronic inflammation causes fatty plaques to form and block arteries, leading to heart attacks, strokes and kidney disease. 

Permanently raised levels of cytokines eventually reduce the effectiveness of the immune system so people become more vulnerable to viruses and show less response to vaccines and their wounds heal slowly. Chronic inflammation is linked to diabetes, cancer and possibly mental illness.

Animal studies show that chronic stress alters the brain in a similar way to that seen in humans with depression and anxiety disorders.

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It’s suggested that the high levels of depression and anxiety disorders in the UK today may partly be due to changes in the brain induced by chronically high levels of cytokines and stress hormones.

Stress may even affect our DNA by degrading the tiny coverings called telomeres at the ends of our chromosomes that protect the DNA in our cells, much like the caps on the ends of shoelaces prevent fraying.

We know that telomere length is an indicator of how quickly cells are ageing. Short telomeres in immune system cells have been linked to many age-related diseases including cancer, diabetes and cardiovascular disease.

It seems likely that this is one of the ways in which stress can fundamentally affect our bodies and our healthspan (the number of years lived in good health).

Research in 2015 by the University Medical Centre Groningen in the Netherlands found that stressful experiences including divorce, unemployment and bereavement seem to hasten the shortening of our telomeres.

Stress is also a risk factor for dementia. Work from the University of Essex shows that older people who have experienced a lot of stress tend to perform worse on cognitive tasks than others, with short-term memory particularly vulnerable.

And a recent study from Harvard Medical School in the U.S. has implicated stress in the shrinking of the brain. It seems healthy people in their 50s and 60s with higher levels of the stress hormone cortisol had smaller brain volumes than those with lower levels.

Stress could even be the reason your hair turns grey. One study from the University of Alabama in the U.S. found a link between the body’s response to stress and infection and the cells responsible for hair colour. Clearly, stress is bad news for your healthspan.

  • The Twinstitute is on BBC2 on Wednesdays at 8.30pm.

The power of classical music 

High blood pressure is a factor in diseases that undermine our ability to enjoy a healthier, longer life.

One cheap and effective tool to help reduce it is to listen to music, but not all types of music are equal, it seems.

Research from the University of San Diego in the U.S. found that classical music cut blood pressure more significantly than jazz, rock or pop.

A study by the University of Oxford found that pieces which matched the rhythm of the body, for instance the repeated ten-second rhythm in works such as Verdi’s Va Pensiero, Puccini’s Nessun Dorma and Beethoven’s 9th Symphony adagio, were the best for slowing heart rate and lowering blood pressure.

Faster classical music such as an excerpt from Vivaldi’s Four Seasons, had no effect on heart rate but the Red Hot Chili Peppers increased it.

Classical music may also improve concentration, as we found in an experiment for The Twinstitute. 

Chris listened to Mozart on headphones as he filled in an online test while sitting in the passenger seat of Xand’s badly driven dodgem car.

The distractions were immense, but, as long as the volume was loud enough, Chris could think clearly and he scored the same (49/50) as in a silent environment.

Take the stress test

We can become so used to the demands of modern life that being in a constant state of stress seems normal. 

To find out if you are in fact living with chronic stress, try this ten-point stress audit devised recently by Manfred Kets de Vries, a clinical professor of leadership development and organisational change at the Insead business school near Paris. 

If you answer ‘Yes’ to six or more of his questions, you should take steps to lower your stress levels.

We can become so used to the demands of modern life that being in a constant state of stress seems normal

1. Do you feel you have too many things on your plate?

2. Do you often feel confused, anxious, irritable or tired?

3. Are you arguing more with your family, friends or colleagues?

4. Are negative thoughts and feelings affecting your home and work life?

5. Is your home or work life no longer giving you any pleasure?

6. Do you feel overwhelmed by the demands of emails and social media

7. Do you feel that you life has become a never-ending treadmill?

8. Are you prone to serious pangs of guilt every time you try to relax?

9. Have you recently experienced a life-altering event such as divorce, a new job, redundancy, retirement, financial difficulties, illness or death in the family?

10. When you are stressed out, do you feel that you have no one to talk to?    

Trick of the mind to relieve the pressure

Mindfulness can have huge benefits for reducing stress — in turn, helping you live well for longer.

Mindfulness is tricky to define, but most people agree it’s the process of paying attention to the present moment in a non-judgmental manner (i.e. without emotion) by making yourself aware of your breathing. This effectively focuses your attention on something other than your stressful thoughts.

Chris tries to spend five minutes every day in mindful meditation. This began in his mid-20s on a trip he made to Nepal for a Channel 4 programme called Medicine Men Go Wild, investigating traditional healing methods.

Mindfulness can have huge benefits for reducing stress — in turn, helping you live well for longer

Chris spent time meditating with Buddhist monks and, over the years, he encountered more people convinced of the benefits of this practice. He was also aware of how many of the stressful aspects of his life were caused by his response to events, rather than the circumstances themselves.

Mindfulness allows him to step back, break the cycle, and give his brain and body a rest from stress hormones. It certainly makes him feel calmer, he says. In his experience, with daily practice it becomes easier to ignore the intrusive thoughts and be more ‘present in the moment’, as the mindfulness gurus say.

The technique has been scientifically investigated since the late Seventies, with thousands of papers published. Scans have shown that mindfulness can lead to physical changes in the brain. 

Pet therapy  

The evidence shows that dog owners are healthier than non-dog owners. One reason is likely to be the daily walk (most pet dogs give you absolutely no choice in the matter).

But another reason is that cuddling a pet releases the brain chemical oxytocin, which has a calming and soothing effect that can help mitigate the negative physiological impact of stress.

In 2004, scientists at the University of Missouri in the U.S. found human blood pressure dropped by 10 per cent around 15 to 30 minutes after stroking a pet.

An earlier study, published in the Western Journal of Nursing Research in 2002, found that people performed better at maths challenges when their pet dog was in the room — even though they weren’t allowed contact.

The evidence shows that dog owners are healthier than non-dog owners

In one experiment, Chris visited a company that allows people to take their pets to work to test this blood pressure-lowering effect during a stressful situation — taking a maths test.

Half-way through the test, the dogs were brought in. Not only did the participants’ blood pressure drop significantly but those whose pets were in the room did far better at the test.

It may be that a pet you love relaxes you in several ways, allowing you to feel safe and possibly changing your place in your local hierarchy, giving you a little more control than you have in a room full of human strangers.

The amygdala — the area that plays a role in stress — shrinks, and grey matter in the pre-frontal cortex, which is responsible for controlling your emotions, thickens. This shows it is doing something.

The most convincing evidence for mindfulness’s benefits comes from its use to help in depression and anxiety. 

Two clinical trials published in The Journal Of Consulting And Clinical Psychology showed it could halve rates of relapse among patients with recurrent depression. It is thought it helps by giving your brain a brief break from the rumination and worrying that characterise anxiety.

The problem is that studies are rarely able to take account of a possible placebo effect (you can’t weed out the potential benefit of the extra attention, guidance and time spent in a relaxing environment that taking part in such a study can involve). But even accounting for a placebo effect, mindfulness seems to be as effective as antidepressants — and has no side-effects.

The National Institute for Health and Care Excellence advocates mindfulness-based cognitive therapy for the treatment of recurrent depression in adults.

Research suggests it may also help with pain — but it’s unclear whether it reduces the intensity of pain or simply improves patients’ ability to cope with it.

In one of our experiments for The Twinstitute, we decided to pitch mindfulness against swearing to see which worked better for reducing pain.

Why swearing? Well, a study at Keele University in 2017 found that volunteers could tolerate mild pain for 50 per cent longer and their perception of pain decreased when they were allowed to swear. The theory is that swearing triggers the natural endorphin-based painkillers of our body’s ‘fight or flight’ response. Interestingly, the stronger the swear word, the stronger the painkilling effect.

For The Twinstitute experiment, we both had to plunge a hand into iced water to see how long we could keep it there.

It was excrutiating. Chris managed two minutes and 56 seconds. But when he repeated the experiment using his mindfulness tactics, he was able to manage five minutes. 

Xand then did the same experiment, this time swearing floridly. But this gained him only 40 seconds. We were surprised at how much more effective the mindfulness was.

The pain from iced water comes on gradually, like a very bad headache or toothache, so for the final test we created a different kind of pain: tattoos. 

We had The Twinstitute logo on our toes and tops of our feet — and then the word ‘Twinstitute’ on the soles, the most sensitive area. There was water rather than ink in the needle, but the stabbing pain was just as intense as a permanent tattoo.

Xand found even fulsome swearing offered little support and called time before the torture was complete, leaving him with only the word ‘Twin’ on his foot. Chris says he won’t be rushing to the tattoo parlour any time soon, but mindfulness made him sufficiently zen to get to the end of the process.


Mindfulness is straightforward. Essentially you sit or lie still and focus on your breath going in and out, and try to slow it down.

If your mind wanders (and it will), you just have to gently draw your attention back to your breathing.

A psychologist friend of ours has likened the thoughts that occur during meditation to trains coming into a station. Just because the train arrives, it doesn’t mean you have to get on it. Let the train leave the station and get back to the breathing.

The idea is to stop yourself engaging with the negative thoughts that will inevitably pop into your head.

You should notice immediate benefits, but — like any exercise — you’ll get better (and notice more powerful effects) with practice.

Compiled by Louise Atkinson

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