[Psychophysiological characteristics of the organization and regulation of the daily work-rest cycles for the crew on a prolonged space flight]. / Psikhofiziologicheskie osobennosti organizatsii i reglamentatsii sutochnykh tsiklogramm deiatel'nosti ékipazha v dlitel'nom kosmicheskom polete.

This paper presents the results of analysis of work-rest cycles of the Salyut-6 and Salyut-7 prime crewmembers. The distribution of work-rest cycles within the day, week, month and the flight as a whole, their relation with other components of the time schedule, the effect of various factors involved on the health status and work capacity were studied. It was shown that specified work-rest cycles should be rigorously adhered to. It was demonstrated that proper planning and realization of work-rest cycles, as well as their correction during actual flight with respect to psychophysiological and biorhythmological variations are required to maintain good health condition and high work capacity of crewmembers.

[Principles of organizing efficient work and rest regimens for crews on prolonged space flights]. / Printsipy organizatsii ratsional'nykh rezhimov truda i otdykha ékipazhei v usloviiakh dlitel'nogo kosmicheskogo poleta.

The work-rest cycles of Salyut-6 crews were investigated. Several modifications were detected: 24-hour static regimens (65-70%) and altered regimens (35-30%) with longer or shorter work-rest cycles. It is concluded that in prolonged space flights two regimens are allowed: principal regimens (normal static regimens of work and rest) used throughout the flight, and operational regimens (differing from 24-hour ones) used no more than once every 7-10 days.

[Characteristics of human sleep, circadian periodicity of physiological functions and of work capacity indices in the 1st 24 hours after the transition from an altered to a usual sleep and wakefulness cycle]. / Osobennosti sna, sutochnoi periodiki fiziologicheskikh funktsii i pokazatelei rabotosposobnosti cheloveka v l-e sutki posle perekhoda ot izmenennogo k privychnomu cheredovaniiu sna i bordstvovaniia.

Twelve male test subjects, aged 28 to 40, took part in the studies, in which a normal work-rest cycle was preceded by three types of an altered cycle, to investigate their adaptation-readaptation reactions. The return to the normal work-rest cycle was accompanied by slight changes in physiological functions, work changes was correlated with the type of altered work-rest cycles and with the degree of men's adaptation to them. The return to the normal work-rest cycle proceeded more readily, if adaptation to an altered cycle was incomplete. It is concluded that the required level of work capacity of men that have to vary their work-rest cycles frequently can be maintained by short-term (for 1 to 3 days) cycle alterations.

[Characteristics of human sleep, diurnal periodicity of physiological functions and work capacity indices on the 1st day after a changeover from the usual to split alternation of sleep and wakefulness]. / Osobennosti sna, sutochnoi periodiki fiziologicheskikh funktsii i pokazatelei rabotosposobnosti cheloveka v l-e sutki posle perekhoda ot obychnogo k drobnomu cheredovaniiu sna i bodrstvovaniia.

The effects of sectionated and shifted workrest cycles on diurnal variations of physiological functions, mental performance and sleep parameters have been studied. It has been demonstrated that the first day on sectionated work-rest cycles brings about the least changes. It has been concluded that the sectionated work-rest cycles can be recommended for transitional-based schedules of scientists working in an unusual environment.

[Sleep, diurnal periodicity of physiologic functions, and human work capacity during the 1st day following a phase shift in the sleep--wakefulness cycle]. / Osobennosti sna, sutochnoi periodiki fiziologicheskikh funktsii i rabotosposobnosti cheloveka v 1-e sutki posle sdviga fazy ritma sna--bodrstvovaniia.

Physiological reactions of 35 male test subjects, aged 25-42, were examined during the first day after a 3 to 11 hour work-rest cycle shift within 24 hours. The shift induced noticeable changes in sleep dynamics. Shifts close to inversion (9- and 11-hour) were accompanied by disturbances in the diurnal rhythm of heart rate and may cause deterioration of mental productivity. Negative effects of such time schedules need to be taken into consideration, when developing work-rest regimens for representatives of different occupations.

[Effect of unusual regimens of daily activity and sleep deprivation on the human functional state and work capacity]. / O vliianii neobychnykh rezhimov sutochnoi deiatel'nosti i lisheniia sna na funktsional'noe sostoianie i rabotosposobnost' cheloveka.

Physiological functions, work capacity and sleep characteristics of six healthy test subjects were studied for 30 days. The test subjects adhered to one of the three different regimens (1--sleep from 2.00 a.m. to 10.00 a.m., 2--sleep from 6.00 p.m. to 2.00 a.m., and 3--sleep from 10.00 a.m. to 6.00 p.m.) which were aggravated by 64 hr or 72 hr vigilance during the experiment. The studies demonstrated general and specific changes in physiological functions, work capacity and sleep closely associated with the fact how far work-rest cycles were shifted and how long they were applied. Prolonged vigilance caused similar changes in physiological functions, work capacity and sleep. The test subjects showed very poor tolerance to an alteration in the work-rest cycle combined with sleep deprivation.

Peculiarities of human sleep in the case of double alternation of "sleep-waking" cycles.

The dynamics of sleep was studied in seven healthy subjects in two schedules, differing in the magnitude of the sleep intervals and their distribution over the 24 hour period. The first series provided for the use of two four-hour sleep intervals, the second six- and two-hour intervals. The investigations showed that the transition to a new schedule was accompanied by substantial qualitative and quantitative sleep disturbances, followed by a restoration of sleep as the subjects adapted. Less pronounced sleep disorders and more rapid restoration were observed in the schedule with nonuniform distribution of the intervals; more pronounced sleep disorders and a slowed restoration of sleep were observed on the schedule with two four-hour intervals.

[Effect of prolonged unidirectional migration of the sleep--wakefulness rhythm phase on human physiological functions, mental productivity and sleep]. / Vliianie dlitel'noi odnonapravlennoi migratsii fazy ritma son-bodrstvovanie na fiziologicheskie funktsii, psikhicheskuiu produktivnost' i son cheloveka.

The paper gives the results of three 30-day experiments carried out to study the effect of migration of the sleep--alertness cycle on physiological functions, psychic productivity and sleep of man. The migration was agravated by the initial change of the cycle which varied from +/- 7 to +/- 11 hours. All test subjects showed a counter-clockwise migration which amounted to a 1.5 hour shift every 4-5 days. All test subjects demonstrated functional cerebral changes, decline of psychic productivity and sleep disorders. The level of those disturbances depended on the value of the initial shift of the sleep--alertness cycle and on the cumulation of the migration effect. Those disorders were noted even when the prechanged sleep--alertness cycle approximated the normal pattern as a result of migration. The results indicate that the migrating day--night pattern, particularly in combination with the initial shift of the sleep--alertness cycle, cannot be recommended for manned space missions. Good health condition and high work capacity of cosmonauts can be maintained, only if a 24-hour sleep--alertness cycle with a normal sleep pattern is provided.