0:00:00 > 0:00:00- Subtitles
0:00:00 > 0:00:02- Subtitles- - Subtitles
0:00:04 > 0:00:06- We're all different.
0:00:07 > 0:00:09- We all live a life - that's unique to us.
0:00:10 > 0:00:12- From our first breath...
0:00:12 > 0:00:14- ..throughout our life...
0:00:15 > 0:00:16- ..we learn and change...
0:00:16 > 0:00:19- ..we learn and change...- - ..as we adapt to our surroundings.
0:00:20 > 0:00:22- I'm Dr Anwen Jones, - a Physiology lecturer...
0:00:22 > 0:00:25- ..at Cardiff Metropolitan - University.
0:00:26 > 0:00:31- I'm Dr Katie Hemer, a Bioarchaeology - specialist at Sheffield University.
0:00:32 > 0:00:36- We'll look at the key developmental - steps for body and brain...
0:00:37 > 0:00:41- ..as we grow, mature and welcome - new members to our midst.
0:00:42 > 0:00:46- In each programme, we focus - on a specific stage of our life.
0:00:47 > 0:00:50- This is our journey through life.
0:00:56 > 0:01:00- Adulthood
0:01:03 > 0:01:08- Once we reach adulthood, we face a - world that's full of responsibility.
0:01:09 > 0:01:14- It's a long, busy period which - stretches from our late teens...
0:01:14 > 0:01:18- ..through to our middle age years - and beyond.
0:01:18 > 0:01:21- What happens to the body - during adulthood?
0:01:22 > 0:01:23- And what about the brain?
0:01:24 > 0:01:28- Does it continue to develop - and change during our adult years?
0:01:36 > 0:01:39- We all look a bit like our parents.
0:01:39 > 0:01:43- We pass on information - from one generation to the next...
0:01:43 > 0:01:45- ..through genetic heredity.
0:01:49 > 0:01:53- Every aspect of a person, - from hair colour to ear shape...
0:01:53 > 0:01:55- ..and even height...
0:01:55 > 0:01:57- ..is decided by our genes.
0:01:59 > 0:02:01- How does heredity work?
0:02:03 > 0:02:08- Does upbringing and environment have - a direct impact on our development?
0:02:10 > 0:02:16- I'm at Swansea University to meet - Dr Heledd Iago and find out more.
0:02:17 > 0:02:18- Heledd, what is heredity?
0:02:19 > 0:02:23- The information which makes us - who we are is stored in our DNA.
0:02:24 > 0:02:27- Every person's DNA - is totally unique.
0:02:28 > 0:02:32- Half the information comes our - mother and half from our father.
0:02:32 > 0:02:35- That information - is stored in the genes.
0:02:36 > 0:02:39- We have a gene - for eye colour, for example.
0:02:39 > 0:02:44- We carry different forms of genes, - which are called alleles.
0:02:44 > 0:02:49- There's a brown eyes allele, - a blue eyes allele...
0:02:49 > 0:02:52- ..and a green eyes allele.
0:02:54 > 0:02:58- Each parent - carries two eye colour alleles.
0:02:59 > 0:03:05- As we only inherit one of these - alleles from Mam and one from Dad...
0:03:06 > 0:03:10- ..we can inherit - different combinations of alleles...
0:03:10 > 0:03:12- ..from our parents.
0:03:13 > 0:03:17- In addition to this, one allele - can be dominant to the other.
0:03:20 > 0:03:23- The brown eye allele - is dominant to the blue eye allele.
0:03:24 > 0:03:29- In this case, although both parents - carry brown and blue eye alleles...
0:03:30 > 0:03:32- ..as brown is dominant...
0:03:33 > 0:03:38- ..there's a three-in-four chance - their children will have brown eyes.
0:03:38 > 0:03:42- Many different things - can affect the way our genes work.
0:03:43 > 0:03:47- More then one gene - can actually have the same effect.
0:03:47 > 0:03:51- For example, many different genes - affect a person's height.
0:03:52 > 0:03:57- What effect does environment and - upbringing have on our development?
0:03:59 > 0:04:02- DNA gives us a foundation - for what we could become...
0:04:02 > 0:04:05- ..if we have good nutrition - and nurture.
0:04:06 > 0:04:09- If I have a set of genes - which mean I should be tall...
0:04:09 > 0:04:13- ..but my parents don't give me - the nourishment I need...
0:04:14 > 0:04:15- ..I won't grow to be tall.
0:04:16 > 0:04:21- What has the greatest impact on - our development - nature or nurture?
0:04:22 > 0:04:26- Nature has a huge impact on us - and we can't control it.
0:04:27 > 0:04:31- We can't control the genes - we inherit from our parents.
0:04:31 > 0:04:35- What we can control, to a degree, - is the environment...
0:04:35 > 0:04:38- ..which affects - our development and growth.
0:04:38 > 0:04:41- We can stay healthy, - go to the gym...
0:04:41 > 0:04:45- ..and avoid things - which will impair our development.
0:04:46 > 0:04:49- We can strive - to fulfil our potential.
0:04:50 > 0:04:55- Our childhood environment has a - direct impact on our development...
0:04:55 > 0:04:59- ..by influencing the genes - we inherit from our parents.
0:04:59 > 0:05:03- Obesity is one example - of nurture's impact on the body.
0:05:04 > 0:05:06- It's a big problem - in modern-day Wales.
0:05:07 > 0:05:10- Over half of Welsh adults - are overweight or obese.
0:05:10 > 0:05:14- I discussed obesity with - the dietician, Sioned Quirke.
0:05:16 > 0:05:21- Sioned, obesity levels among Welsh - adults are higher than ever before.
0:05:22 > 0:05:26- Yes, and those levels - continue to increase year upon year.
0:05:26 > 0:05:30- We have the highest - adult obesity levels in the UK.
0:05:32 > 0:05:34- Is there an explanation for it?
0:05:34 > 0:05:36- Is there an explanation for it?- - We're busier, so we don't cook.
0:05:37 > 0:05:41- We buy ready meals from supermarkets - and heat them up...
0:05:41 > 0:05:46- ..and they tend to be more calorific - than home cooked meals.
0:05:47 > 0:05:49- We never walk anywhere either.
0:05:49 > 0:05:54- Obesity levels are so high, it's - almost normal to be overweight...
0:05:55 > 0:05:57- ..rather than - to be a healthy weight.
0:05:58 > 0:06:01- There are lots of reasons for it.
0:06:02 > 0:06:06- Our lifestyle certainly contributes - to obesity levels.
0:06:07 > 0:06:11- Yes, lifestyle and nurture - make it easy to be overweight...
0:06:11 > 0:06:14- ..and very difficult to lose weight.
0:06:16 > 0:06:19- What impact does this have - on our long-term health?
0:06:20 > 0:06:23- Many people - are obese from a young age...
0:06:23 > 0:06:27- ..and they don't think it - affects them, so it doesn't matter.
0:06:28 > 0:06:31- In reality, it will - catch up with them eventually.
0:06:32 > 0:06:37- We see high levels of diabetes, - heart disease, cancer...
0:06:37 > 0:06:39- ..and joint pain.
0:06:41 > 0:06:45- Obesity affects - every aspect of our health.
0:06:45 > 0:06:47- Can our actions as a child...
0:06:49 > 0:06:52- ..contribute to obesity - when we're adults?
0:06:52 > 0:06:54- Yes.
0:06:54 > 0:06:57- From a very young age, - we're predisposed...
0:06:58 > 0:07:01- ..to these ideas - of how we eat, how we live...
0:07:01 > 0:07:03- ..and how much exercise we get.
0:07:04 > 0:07:08- As we grow up, we learn - from different people around us.
0:07:08 > 0:07:12- That's why our families - are incredibly important...
0:07:12 > 0:07:15- ..right from the moment we're born.
0:07:15 > 0:07:18- It has a huge impact - on our behaviour in adulthood.
0:07:20 > 0:07:25- At Tir na n-Og Child Research - Centre, Bangor University...
0:07:25 > 0:07:30- ..Catherine Sharp looks at the - impact of early intervention...
0:07:30 > 0:07:34- ..on a child's attitude towards - a healthy diet and exercise.
0:07:35 > 0:07:38- It's crucial - to target young children...
0:07:38 > 0:07:42- ..because that's when they learn - what food they like.
0:07:42 > 0:07:47- Our research's aim is to create - a fun, enjoyable programme...
0:07:47 > 0:07:51- ..which gets chilren - eating fruit and vegetables.
0:07:51 > 0:07:55- It's not about seeing or smelling. - It's about eating it.
0:07:56 > 0:07:58- Behaviours - which you learn at a young age...
0:07:59 > 0:08:01- ..are repeated over the years.
0:08:01 > 0:08:06- If we can get them eating fruit - and vegetables at a young age...
0:08:06 > 0:08:08- ..we hope they carry on - and be healthy.
0:08:09 > 0:08:12- These three - and four-year-old children...
0:08:13 > 0:08:17- ..follow a healthy eating programme - called Food Dudes.
0:08:17 > 0:08:23- Through this, they taste food like - strawberries and raw broccoli...
0:08:24 > 0:08:26- Who likes broccoli?
0:08:27 > 0:08:29- ..which young children rarely enjoy.
0:08:30 > 0:08:33- They're rewarded - for eating a portion.
0:08:33 > 0:08:37- They do this several times - as research shows...
0:08:37 > 0:08:41- ..children must try food at least - ten times before they like it.
0:08:42 > 0:08:46- Before they started the programme, - they refused to eat raw broccoli.
0:08:47 > 0:08:49- Over time, we stop rewarding them...
0:08:50 > 0:08:52- ..but they still eat - the fruit and veg.
0:08:53 > 0:08:55- Have you seen a difference?
0:08:55 > 0:08:59- Yes, and children who are part - of the intervention scheme...
0:08:59 > 0:09:04- ..eat more fruit and veg than - children given fruit and veg...
0:09:04 > 0:09:06- ..without the intervention.
0:09:07 > 0:09:11- Placing food in front of them - doesn't have as strong an impact...
0:09:12 > 0:09:13- ..as our programme.
0:09:16 > 0:09:21- Catherine's research also looks at - physical activity among children.
0:09:23 > 0:09:27- Children watch a DVD - featuring characters and a story.
0:09:27 > 0:09:31- The children must copy - the characters' movements...
0:09:31 > 0:09:35- ..which means they get some exercise - as they watch.
0:09:35 > 0:09:40- They wear tabards which include - activity-monitoring devices.
0:09:41 > 0:09:43- The children seem to enjoy it.
0:09:46 > 0:09:51- A positive attitude towards food - and exercise when we're young...
0:09:51 > 0:09:55- ..has a positive effect on us - when we're older too?
0:09:56 > 0:10:00- Yes, and that's why it's vital - to target young children.
0:10:00 > 0:10:03- Give children - the best possible start...
0:10:04 > 0:10:06- ..and hope - they become healthy adults.
0:10:07 > 0:10:12- Early intervention is likely - to change our long-term attitude...
0:10:12 > 0:10:16- ..towards healthy eating - and exercise as we become adults.
0:10:17 > 0:10:20- Programmes like this - could play a vital role...
0:10:20 > 0:10:23- ..in the battle against obesity.
0:10:27 > 0:10:31- Coming up, we interrupt the brain - and compare skeletons...
0:10:32 > 0:10:35- ..as we examine - the development of an adult.
0:10:36 > 0:10:36- .
0:10:40 > 0:10:40- Subtitles
0:10:40 > 0:10:42- Subtitles- - Subtitles
0:10:50 > 0:10:55- Once we've learned a skill like - driving, it comes naturally to us.
0:10:55 > 0:10:59- We don't have to think too much - about what we're doing.
0:11:01 > 0:11:03- The brain - processes these messages...
0:11:04 > 0:11:07- ..and reacts - by giving the body instructions.
0:11:07 > 0:11:11- Things like 'move your arm' - or 'tilt your head'.
0:11:12 > 0:11:13- How does the brain do this?
0:11:14 > 0:11:17- Where does this control stem from?
0:11:19 > 0:11:23- I'm at CUBRIC, - Cardiff University...
0:11:23 > 0:11:28- ..where they work to understand - how we control our movements.
0:11:28 > 0:11:31- This research is a huge challenge...
0:11:32 > 0:11:37- ..as they try to get a snapshot of - what part of the brain is working...
0:11:38 > 0:11:41- ..and how the brain functions - at the same time.
0:11:42 > 0:11:46- New technology has been developed - in order to achieve this.
0:11:46 > 0:11:52- Transcranial Magnetic Stimulation - is used to cause brain activity.
0:11:52 > 0:11:58- The TMS sends a magnetic pulse - into a specific part of the brain...
0:11:58 > 0:12:02- ..and this has a direct impact - on the activity in that area.
0:12:04 > 0:12:05- In this case...
0:12:05 > 0:12:10- ..the TMS targets the area of the - brain which controls hand movement.
0:12:12 > 0:12:14- That's what - caused Rhydian's hand to move.
0:12:15 > 0:12:19- In order to look at - the active area of the brain...
0:12:19 > 0:12:24- ..Rhydian lies in an MRI scanner, - where his brain will be monitored...
0:12:24 > 0:12:26- ..as he performs a task.
0:12:28 > 0:12:33- How important is our control - over movement in our everyday life?
0:12:33 > 0:12:36- It's a constant process - but we're unaware of it.
0:12:37 > 0:12:41- When the lights change at traffic - lights, should you go or stop?
0:12:41 > 0:12:45- That's the kind of decision - which is controlled by this system.
0:12:46 > 0:12:50- If I want to perform a movement, - what happens in my brain?
0:12:50 > 0:12:54- Several areas of your brain are - active during voluntary movement.
0:12:55 > 0:13:00- When you decide to move, the signal - comes from the motor cortex...
0:13:00 > 0:13:03- ..at the top of the brain.
0:13:03 > 0:13:07- That signal must travel through - several areas of the brain...
0:13:08 > 0:13:13- ..and other areas can connect - to that area to form a network.
0:13:14 > 0:13:17- The central brain areas - integrate that data...
0:13:17 > 0:13:21- ..to decide whether or not - you should slam on the brakes.
0:13:21 > 0:13:25- Why do you use TMS - to affect people's behaviour?
0:13:26 > 0:13:29- In this experiment, - Rhydian performed tasks...
0:13:29 > 0:13:32- ..where he had make - quick decisions.
0:13:33 > 0:13:38- We apply TMS at that precise moment - when he's trying to make a decision.
0:13:38 > 0:13:43- This should show us how the network, - or the activity changes.
0:13:45 > 0:13:48- We're ready to go, - so here's your first scan.
0:13:48 > 0:13:53- Rhydian must respond to instructions - which tell him to move...
0:13:54 > 0:13:56- ..but sometimes, he's told to stop.
0:14:00 > 0:14:05- The MRI scanner can show us - what part of the brain is active...
0:14:05 > 0:14:07- ..when the task is performed.
0:14:08 > 0:14:12- The TMS can directly affect - the way the brain works.
0:14:12 > 0:14:15- It targets areas of the brain...
0:14:16 > 0:14:18- ..which are vital - to voluntary movement.
0:14:19 > 0:14:22- Researchers use MRI images - to spot brain activity...
0:14:23 > 0:14:27- ..as Rhydian controls his movements - with and without TMS.
0:14:28 > 0:14:31- We're not looking for - changes in the brain activity...
0:14:32 > 0:14:36- ..directly below the area - of the brain we're stimulating.
0:14:37 > 0:14:40- We're looking for change - further down the brain.
0:14:40 > 0:14:45- Several areas are important - to this decision-making process...
0:14:46 > 0:14:50- ..and they lie between - the motor cortex and the brainstem.
0:14:50 > 0:14:53- We study any differences - in the movement...
0:14:54 > 0:14:56- ..when the TMS pulse is applied.
0:14:57 > 0:15:00- Where will this work lead - in the future?
0:15:00 > 0:15:03- We're studying young adults...
0:15:03 > 0:15:07- ..to better understand - this voluntary movement network.
0:15:08 > 0:15:12- We will then take this research work - and apply it to older adults...
0:15:13 > 0:15:18- ..to try to understand how this - network changes as we get older.
0:15:20 > 0:15:24- One of the main symptoms - of Parkinson's disease...
0:15:25 > 0:15:27- ..is an inability - to control movements.
0:15:28 > 0:15:31- Understanding - how a healthy person does this...
0:15:31 > 0:15:34- ..and how control changes - during our lifetime...
0:15:34 > 0:15:39- ..will help researchers - understand Parkinson's...
0:15:39 > 0:15:41- ..and maybe lead to a new treatment.
0:15:42 > 0:15:46- Our bodies change very little - during adulthood...
0:15:46 > 0:15:50- ..but when we hit 40, - it begins to change noticeably.
0:15:51 > 0:15:53- Middle-aged men and women - gain weight.
0:15:54 > 0:15:57- Men tend to gain belly fat after 40. - Why is that?
0:15:57 > 0:16:01- One theory is that it's easier - to carry fat around on the waist...
0:16:01 > 0:16:04- ..than any other part of the body.
0:16:04 > 0:16:09- That left Neanderthal man free to - hunt without being impeded by fat.
0:16:09 > 0:16:14- We lose muscle mass as we get older - and our metabolic rate slows down.
0:16:14 > 0:16:18- That means we burn around ten fewer - calories every day.
0:16:18 > 0:16:20- But how many of us eat less?
0:16:21 > 0:16:25- By the age of 55, the female body - has undergone huge change...
0:16:25 > 0:16:28- ..and she goes through - the menopause.
0:16:28 > 0:16:31- The ovaries - no longer release eggs...
0:16:31 > 0:16:35- ..and the levels - of oestrogen and progesterone drop.
0:16:35 > 0:16:39- It may be no coincidence that we - live long past reproductive age.
0:16:40 > 0:16:44- Adults who are middle-aged and older - are valuable to society.
0:16:44 > 0:16:46- They're a mine of information...
0:16:46 > 0:16:50- ..and they can pass on knowledge - to the next generation.
0:16:50 > 0:16:55- I'm a Bioarchaeologist who - specializes in bones and skeletons.
0:16:56 > 0:16:59- The skeleton changes a lot - during our life...
0:17:00 > 0:17:02- ..even during adulthood.
0:17:03 > 0:17:07- Studying bones offers countless - clues about humans in the past.
0:17:07 > 0:17:12- How does the skeleton change - during childhood and adulthood?
0:17:13 > 0:17:17- These two individuals - lived over 1,000 years ago.
0:17:18 > 0:17:21- This child was around six years old.
0:17:21 > 0:17:23- This man was at least 40 years old.
0:17:24 > 0:17:28- A normal adult has 206 bones.
0:17:29 > 0:17:34- When we're born, there are - over 300 sections in our skeleton.
0:17:35 > 0:17:39- There's an obvious difference - in the sizes of the bones...
0:17:40 > 0:17:43- ..but we can look at other features - on the skeleton...
0:17:44 > 0:17:46- ..to reveal this person's exact age.
0:17:48 > 0:17:53- As the skeleton develops, - the bones grow...
0:17:54 > 0:17:58- ..and different sections fuse - to create a complete, mature bone.
0:17:58 > 0:18:04- Bone fusion happens across the - whole skeleton at different times.
0:18:05 > 0:18:10- I can use this information - to age any particular individual.
0:18:10 > 0:18:12- I also look at teeth.
0:18:13 > 0:18:16- They develop and appear - at specific times.
0:18:18 > 0:18:22- What about the skeleton - of an adult who's stopped growing?
0:18:23 > 0:18:25- You can age a mature skeleton...
0:18:26 > 0:18:30- ..by looking at several features - linked to physiological decline.
0:18:31 > 0:18:34- In a mature adult, - I'd expect to see...
0:18:34 > 0:18:37- ..more wear - on the teeth's chewing surface.
0:18:39 > 0:18:44- I also look for changes in bones' - surface, for example in the pelvis.
0:18:44 > 0:18:48- Bones can reveal a lot about - diseases which develop over time.
0:18:48 > 0:18:51- This change suggests to me...
0:18:51 > 0:18:55- ..that this person suffered from - a disease such as arthritis.
0:18:58 > 0:19:02- Osteoporosis is another condition - which affects the bones.
0:19:02 > 0:19:06- It's a condition - in which bones become fragile.
0:19:07 > 0:19:11- One in three women over 50 - and one in five men suffer from it.
0:19:12 > 0:19:17- An adult's lifestyle is likely to - affect the strength of their bones.
0:19:17 > 0:19:23- Katie is at the Institute Of - Molecular & Experimental Medicine...
0:19:24 > 0:19:28- ..to meet Dr Bronwen Evans, - who specializes in osteoporosis.
0:19:32 > 0:19:37- Osteoporosis happens when cells - in the bone don't function properly.
0:19:38 > 0:19:41- There are two types of bone cells...
0:19:42 > 0:19:45- ..namely osteoclasts - and osteoblasts.
0:19:47 > 0:19:51- Osteoclasts break down - bone tissue and create holes.
0:19:51 > 0:19:55- They communicates - with the osteoblasts...
0:19:55 > 0:20:00- ..and the osteoblasts deposit - new bone tissue to fill those holes.
0:20:00 > 0:20:04- You need balance between - the osteoclasts and the osteoblasts.
0:20:04 > 0:20:07- When that balance is lost...
0:20:07 > 0:20:11- ..less bone tissue is created - and osteoporosis takes hold.
0:20:12 > 0:20:14- You have an example of that here.
0:20:14 > 0:20:16- You have an example of that here.- - Yes. This is a normal bone.
0:20:19 > 0:20:23- You can see the wall here - and a little bit of bone structure.
0:20:24 > 0:20:27- This is one - which is affected by osteoporosis.
0:20:29 > 0:20:33- You can see that the wall is thinner - and much of the structure is lost.
0:20:34 > 0:20:38- This bone is much more brittle - and it will break far easier.
0:20:39 > 0:20:41- Bone is a dynamic tissue...
0:20:41 > 0:20:45- ..which the body constantly - breaks down and remodels.
0:20:45 > 0:20:48- Our capacity to do this - changes as we get older.
0:20:49 > 0:20:51- Bones get stronger - during childhood...
0:20:52 > 0:20:57- ..and they're at their strongest - when we're around 25 years old.
0:20:57 > 0:21:00- From the age of 35, - our bones naturally start to weaken.
0:21:01 > 0:21:05- Our lifestyle can affect - the amount of bone density we lose.
0:21:05 > 0:21:09- When does osteoporosis affect us?
0:21:09 > 0:21:11- When does osteoporosis affect us?- - It can hit you at any time.
0:21:11 > 0:21:15- The most important thing you can do - to halt this condition...
0:21:15 > 0:21:18- ..is to adopt a healthy lifestyle.
0:21:18 > 0:21:20- Eat a calcium-rich diet...
0:21:21 > 0:21:25- ..get enough sun to absorb - the vitamin D your bones need.
0:21:25 > 0:21:29- Get some exercise, - especially weight-bearing exercise.
0:21:30 > 0:21:35- Weight-bearing exercise stimulates - the creation of new bone tissue...
0:21:35 > 0:21:39- ..which strengthens the skeleton.
0:21:39 > 0:21:44- To see how weight-bearing exercise - helps increase bone density...
0:21:45 > 0:21:50- ..Bronwen's team focuses on the - bone's third cell - the osteocyte.
0:21:50 > 0:21:54- These cells sense the pressure - on the bone structure.
0:21:54 > 0:21:57- It communicates - with the osteoblast...
0:21:58 > 0:22:03- ..which reacts by creating new bone - and strengthening existing bone.
0:22:03 > 0:22:07- These cells are embedded - deep in the bone matrix...
0:22:07 > 0:22:12- ..and Bronwen's team created a - new technique to see how they work.
0:22:12 > 0:22:16- They grew osteocytes on - a 3D structure in the laboratory.
0:22:17 > 0:22:21- They developed a machine - which puts pressure on the cells...
0:22:22 > 0:22:27- ..that is equivalent to the pressure - exercise puts on the skeleton.
0:22:27 > 0:22:32- This technique allows Bronwen's team - to study the effect of weight...
0:22:33 > 0:22:34- ..on the osteocytes.
0:22:35 > 0:22:39- This means they can gauge how - they react within the bone itself.
0:22:41 > 0:22:44- By understanding - exactly how that works...
0:22:45 > 0:22:49- ..we hope to create new medication - to treat osteoporosis.
0:22:53 > 0:22:56- Adulthood is a long period...
0:22:56 > 0:23:01- ..during which we leave home, - create a career and have children.
0:23:02 > 0:23:07- Our bodies reach full maturity - and we stop growing.
0:23:08 > 0:23:12- But our brain constantly adjusts - to the complex world around us.
0:23:13 > 0:23:18- We amass experience and knowledge - to share with the next generation.
0:23:19 > 0:23:22- Lifestyle has a long-term impact - on the body...
0:23:22 > 0:23:24- ..which changes once again...
0:23:25 > 0:23:30- ..as we pass through our middle-aged - years and reach our final chapter.
0:23:30 > 0:23:33- Next time, we test body and brain...
0:23:34 > 0:23:37- ..as we focus on later life.
0:23:51 > 0:23:53- S4C subtitles by Eirlys A Jones
0:23:53 > 0:23:53- .