On the occasion of World Sleep Day, Professor Juan Antonio Madrid, Head of the CIBER Group on Frailty and Healthy Aging (CIBERFES) at the University of Murcia, talks to us about his work on chronodisruption and aging
The group led by Professor Madrid at the University of Murcia works in the field of Chronobiology and focuses its interest on the development of strategies and new technologies to assess and prevent chronodisruption (circadian rhythm disturbances) and their consequences on the health of the circadian system, and therefore, on the general well-being and health of particularly sensitive populations, such as the elderly.
Following your studies on chronobiology, how do circadian rhythms influence health?
More than thirty-five years working in the field of Chronobiology have convinced me that sleep, along with nutrition, physical activity and a good attitude and mental activity, is part of the four pillars of health. By taking care of these aspects, it is possible that we will not be able to avoid all diseases, but we will be able to improve the quality of life and reduce the risk of dependency during the last years of life.
What are the pathologies in which chronodisruption can be considered a key risk factor?
Sometimes we find people displaying disorganized, irregular, low amplitude or non-existent rhythms, or even completely out of sync with natural day and night. In these cases we speak of chronodisruption. Today we know that chronodisruption aggravates and favors the appearance of numerous pathologies closely linked to developed societies, such as: cognitive deterioration, depression, insomnia, accelerated aging, diabetes, cardiovascular diseases, cancer, immunosuppression and infertility, among others.
Has progress been made in the knowledge of the biological mechanisms by which chronodisruption has these negative effects on health?
Studies that show the association between chronodisruption and a large number of pathologies are relatively abundant, although few shed light on the mechanisms that explain these effects. However, if we take into account that more than 15% of the entire genome of the cell is controlled by the circadian clockwe will easily understand that the alteration of this machinery could affect the temporal organization of the different functions that take place in the cell, something similar to what would happen in an orchestra in which the musicians each played the score without paying attention to their director.
In addition to contributing to show the relationship between chronodisruption and some diseases, such as melanoma, colorectal cancer, cognitive impairment, obstructive sleep apnea, metabolic syndrome…, our Chronobiology laboratory () is especially interested in two much lesser-known fields: the detection of chronodisruption markers using objective techniques and the development of corrective or chronopotentiation measures.
In the elderly, after nap time, activity is considerably reduced and episodes of drowsiness appear
Is there a clear relationship between biological rhythms and aging?
Of course. Besides, the relationship between biological rhythms and aging is bidirectional. On the one hand, when we analyze the rhythms in an aged person we can detect a series of differential characteristics that allow us to know their chronobiological age; on the other hand, when a person is exposed to situations that cause chronodisruption, their aging markers rise. This has been verified, especially, in laboratory animals that are exposed to abnormal light-dark cycles and in which premature aging is detected, especially when the animals have a previous pathology. Animal models of accelerated aging have also been created, experimentally removing one of the genes from their circadian clock.
How do circadian rhythms behave in older people?
A biological rhythm of an older person does not necessarily have to be synonymous with an aged rhythm. We have monitored people over 70 years of age with biological rhythms similar to those of a young person and vice versa. However, most of the older ones share a series of characteristics in their rhythms. The first is the loss of amplitude or contrast between day and night. Thus, for example, during the night their sleep is superficial and fragmented, their melatonin is lower and the need to go to the bathroom to urinate increases, while the day is interrupted by one or more naps. The second marker of aging is that of preview of the rhythms. In the case of sleep, it is characterized by early awakenings and the need to go to sleep early. Frequently, after nap time, activity is considerably reduced and episodes of sleepiness appear.
How does chronodisruption affect the development of frailty and premature aging?
The two population groups with the highest incidence of chronodisruption are the elderly and adolescents and young people. The appearance of chronodisruption in the elderly is closely related to three factors: reduced physical activity and increased sedentary lifestyle, decreased light transmission through the lens and diseases such as diabetes, or neurodegenerative diseases such as Parkinson’s or Alzheimer’s. Actually, we should start considering chronodisruption markers as frailty indicators as wellsince the association between both situations is very close.
In the laboratory, several studies have unequivocally shown that exposure to constant lighting or irregular light-dark cycles, such as that of a shift worker, was followed by accelerated aging, shortened lifespan, and increased carcinogenesis in rodents. . In humans, chronic chronodisruption is associated with telomere shortening.
Can chronodisruption prevention strategies be developed in older people?
All non-pharmacological strategies to prevent chronodisruption are based on three principles: increase the regularity of life habits (meals, sleep, physical activity and social contacts); enhancing the contrast between day and night (increasing activity and exposure to light during the day and rest, darkness, and fasting at night); and favor the synchronization of the rhythms to the natural cycle of light-darkness.
Is it possible to reverse the chronodisruption and improve the quality of sleep in people with great frailty caused by neurodegenerative diseases?
The chronodisruption associated with neurodegenerative diseases cannot be reversed; however, there are measures, based on the modification of life habits that can help alleviate its effects. The alteration of circadian rhythms or chronodisruption as a consequence of neurodegeneration occurs mainly for three reasons: one is the loss of communication between the retina and the biological clock; the second is due to the degeneration of the clock itself; and the third to the reduction of the signals that the clock sends to the rest of the organism, as it happens with melatonin.
What non-pharmacological therapies can improve the quality of sleep in the elderly?
The elderly, but also anyone who has sleep problems regardless of their age can benefit from a set of therapies aimed at enhancing regularity, the contrast between day and night and synchronization. It is convenient regularize schedules waking up, meals, physical activity and social contacts. People who maintain great regularity in their lifestyles can maintain a healthy state for longer. Contrast what we do during the day and at night it is another factor that enhances circadian rhythms and improves sleep. The day must be bright, socially connected and active while at night, on the contrary, darkness, silence, fasting and rest must dominate. This contrast is what winds up the biological clock.
Finally, synchronization refers to the convenience of harmonize our internal biological time with environmental time marked by the sun and with the social time that our daily obligations impose on us. We must respect a minimum rest-sleep time and this must occur during the natural night.
Chronodisruption aggravates and favors the appearance of numerous pathologies
To what extent can the unwanted loneliness that many older people experience influence the appearance or worsening of chronodisruption?
Without a doubt, unwanted loneliness, together with the fragility and dependence frequently associated with aging, contributes to chronodisruption. Frequently, the frailty and dependency associated with aging leads to depression, loss of purpose, social and environmental isolation, spending too many hours sitting in front of the television, laziness when cooking, living indoors with poor lighting, or keeping the room clean. lit up with the tv on at night. All of them are factors that enhance circadian disturbances and that very negatively affect the quality of sleep.
Is the chronodisruption greater among older people who live in their own homes or among those institutionalized in geriatric centers?
You cannot give a single answer to this question, everything will depend on the way of life of these people. For example, if they live alone, they may neglect important aspects related to their healthy lifestyle habits, as discussed above, whereas in a modern institution, these habits would be supervised by caregivers and reinforced by social interaction. On the other hand, a person who lives in her house, and remains integrated in the social activities of his town or neighborhood, can perfectly counteract the effects of aging on chronodisruption.
Is medication abused in residences when favoring the soil of the elderly?
In general, sleep medication is abused across the board, both in older people living at home and those living in institutions. This medication is sometimes absolutely necessary, but it is the doctor who must assess the dependency it causes and the risk it entails of falls, for example when the person gets up at night to go to the toilet and is under the influence of said medication.
What would be the basic tips to maintain good circadian health?
From a practical point of view, the ten tips of the biological watchmaker for each day would be:
1 – Perform at least 30 minutes of moderate-vigorous physical activity
2 – Reduce sedentary time to less than 10 hours
3 – Spend at least 2 hours exposed to natural light outdoors (not direct sun)
4 – Disconnect from electronic devices, at least an hour before going to sleep
5 – Eat at least two…