Stages of Sleep and the Menstrual Cycle | Ultradian & Infradian Rhythms

what happens when we sleep is a mystery or is it did you know that when you sleep it typically looks like this and did you know there is a way to nearly always remember your dreams hey everyone welcome back to Bear it in mind in this final video in the bioc psychology topic we are finishing our exploration of biological rhythms biological rhythms are repeated patterns of changes in the body that are regulated by an internal clock previously we explored circadian rhythms these are rhythms that last for around 24 hours the sleep wake cycle is an example of a circadian rhythm which we go through once a day we're also going to refer again to endogenous pacemakers these are the internal biological clocks that regulate our biological rhythms and exogenous zeit gibbers these are the external cues that influence our internal biological clocks so in this video we're going to explore two other rhythms known as infradian and ultradian rhythms circadian rhythms last for around a day whereas infradian rhythms take longer than 24 hours to complete one cycle the example we're going to consider is the menstrual cycle the menstrual cycle is the time from the first day of a woman's period to the day before her next period the length of the menstrual cycle on average is around 28 days but this can vary between 23 to 35 days it's controlled by hormones in the first half of the menstrual cycle levels of the hormone estrogen rise which causes the ovary to develop and release an egg and the lining of the wound begins to thicken in the second half of the cycle the levels of another hormone rise known as progesterone and this helps to maintain the lining of the womb in preparation for implantation of a developing embryo if pregnancy doesn't occur levels of estrogen and progesterone fall and the womb lining comes away and Le leaves the body as the menstrual flow the hormone levels of estrogen and progesterone regulate the timing of this biological Rhythm but are there any external cues any exogenous Z gibbers that can affect the menstrual cycle in 1971 Martha mlto investigated 135 females who all went to the same college and who lived together in dmaries how similar would the onset of their menstrual cycle become they found that a sign ific factor in synchrony is that the individuals of the group spend time together in other words the more time they spent together the more their menstrual cycles changed to be closer together how in the world does this happen What external cue could be influencing the timing of the menstrual cycle well mclintoch herself raised that very question when she wrote whether the mechanism underlying this phenomenon is pheromonal is a question which remains open for investigation pheromonal what does that mean well you may have heard of pheromones before they are thought to be an odorless chemical substance that we release into the environment that affects the behavior of others perhaps these Airborne chemical signals are being detected by the women and it's shaping the timing of when their menstrual cycle starts to answer this question mlin talk conducted another study with a researcher named Kathleen Stern in this study 29 women were involved and pheromones were taken from nine of the women who had worn a cotton pad in their armpit for 8 hours these pads were then rubbed wait for it on the upper lip of the other women at different stages in their menstrual cycles but if it makes you feel any better they did treat the cotton pads with alcohol and freeze them first what they found was at the menstrual cycles for many of the women came closer together 68% of the women's menstrual cycles were more synchronized with the woman whose pheromones were shared than they were at the start of the study suggesting that pheromones might be an exogenous zit giber that can influence the internal biological clock of the menstrual cycle however many criticisms have been made of the research into the role of feromon on the menstrual cycle one of the main issues relates to problems replicating the findings for example one study in 200 6 conducted research with the Striking title of women do not synchronize their menstrual cycles to reexamine the idea of close friends synchronizing their menstrual cycles they collected data on the menstrual cycles of 186 Chinese women living in dormitories with four to eight women living in each room ideal conditions for synchronization if feromon are the mechanism after studying them for over a year they found that these women did not synchron orze their Cycles thus challenging the findings of mlto in fact some researchers have gone so far as to question the whole idea and existence of ferons and their influence on human [Music] behavior our third and final Rhythm are ultradian rhythms ultradian rhythms take less than a day you have more than one cycle of the Rhythm within 24 hours the example we're going to consider are the stages of sleep not to be confused with this sleep wake cycle of the Circadian rhythm one of the ways that psychologists know about the different stages of sleep comes from the recordings of the electrical activity of the brain using eegs Research into sleep using eegs has found distinct brain wave patterns when you and I sleep we sleep in cycles of approximately 90 minutes and during those 90 minute Cycles we go through a series of stages sleep can be divided into two main types nonm sleep and RM sleep RM standing for rapid eye movement nonm sleep is divided into three separate stages known as N1 N2 and N3 with each stage increasing the depth of sleep N1 and N2 are the light stages of sleep and as we go into these lighter stages your heart rate starts to decrease your body temperature starts to drop and your electrical brain wave activity starts to slow down we typically spend around 5 minutes in the N1 stage of sleep before entering N2 N3 is when we enter the deepest stage of sleep which is also known as slow wave sleep it's characterized by signals with much lower frequencies and higher amplitudes known as delta waves this stage is the most difficult to be awakened from for some people even loud noises will not wake them up at the end three stage the body does some amazing things firstly it's when the body repairs and regrows tissues and builds muscles secondly it's crucial to strengthening the immune system and thirdly research also appear to suggest that it's the deep non-rem sleep that helps consolidate memories into our long-term memory getting enough N3 sleep makes you feel refreshed the next day although this is also the stage when sleepwalking and night terrors occur in contrast to non-rem sleep there is REM sleep REM sleep is sometimes known as paradoxical sleep because your brain waves look more like when someone is awake however your sceletal muscles are in a state of paralysis except for the eyes and this is why it's called RM because our eyes start to move rapidly as you may be able to see from the graph the amount of non-rem and REM sleep within a 90minut cycle changes throughout the night with the first half of the night spent mostly in non-r and the second half of the night consisting of more REM sleep and the REM sleep is is when we are thought to dream when we have a full night of uninterrupted sleep a typical sleep cycle progresses through the stages of N1 first then N2 and then N3 but then we go back up to N2 again before entering REM [Music] sleep in a now classic study William deont and Nathaniel clitman used EEG machines to record sleeping and dreaming specifically they wanted to see if there were any differences in dreaming between non-rm and REM sleep there were nine participants in the study seven male and two female but only five of these were studied in detail participants were allowed to eat normally during the day but were not allowed to drink caffeine or alcohol as these are substances that are known to interfere with the quality of our sleep shortly before their normal bedtime they would arrive at the lab where they went to sleep with electrodes from the EG attached to their scalp they found that when they were woken up during non-rem sleep participants could rarely remember their dreams around 7% in contrast when woken up during REM sleep they could often vividly describe their dreams around 80% of the time so if you want to remember your dreams the trick is to wake yourself up during REM sleep therefore this study demonstrates that there are distinct stages to our sleep however Research into the stages of sleep have been criticized in relation to its samples this is because the samples used in these studies are often very small as can be seen with the five studied by DeMont and clitman such a small number makes it hard to generalize the results to others especially when there could be individual differences in people's biology hormones and age which might all influence sleep therefore it could be argued that our understanding of all trading rhythms could be further strengthened with larger samples and finally a further issue with Research into ultran rhythms relates to the settings in which they take place this is because sleep Laboratories are very artificial settings I mean think about it we all know know what it's like sleeping somewhere different for the first time it's usually a terrible night's sleep the bed feels different the pillows are just not right and there are unfamiliar sounds in fact forget about a comfy pillow try going to sleep with Electro stuck to your head and not to mention a bunch of researchers watching you sleep ready to wake you up at any moment studying sleep in this manner could lead to people's sleep stages being altered compared to normal and therefore it could be argued that the research into all trading rhythms lacks ecological validity and it's not reflecting ordinary sleep if this video has got you even more intrigued about the psychology of sleep then I've have link below a list of books and podcasts for you to explore but now it's time to check your understanding of what we've covered in this video I'll present one question at a time you can pause the video to answer it yourself first and then press play again to reveal the [Music] answer [Music] [Music] [Music] I [Music] I hope you found this video helpful and we'll see you in the next one

Channel: Bear it in MIND

Views: 2,073

Keywords: infradian rhythms, ultradian rhythms, biopsychology, dement & kleitman, biopsychology revision, bear it in mind, AQA psychology, biological rhythms, stages of sleep, pheromones, mcclintock, stern and mcclintock, psychboost biopsychology

Id: hH3AwvWcNlc

Length: 12min 21sec (741 seconds)

Published: Thu Feb 22 2024