Piotr Woźniak considers the theory behind severe reduction of total sleep time by way of short naps unsound, arguing that there is no brain control mechanism that would make it possible to adapt to the "multiple naps" system. Wozniak says that the body will always tend to consolidate sleep into at least one solid block, and he expresses concern that the ways in which the polyphasic sleepers' attempt to limit total sleep time, restrict time spent in the various stages of the sleep cycle, and disrupt their circadian rhythms, will eventually cause them to suffer the same negative effects as those with other forms of sleep deprivation and circadian rhythm sleep disorder .  Woźniak further claims to have scanned the blogs of polyphasic sleepers and found that they have to choose an "engaging activity" again and again just to stay awake and that polyphasic sleep does not improve one's learning ability or creativity. [ citation needed ]
Many species of Hoya are popular houseplants in temperate areas (especially H. carnosa ), grown for their attractive foliage and strongly scented flowers . Numerous cultivars have been selected for different leaf forms or flower colours. Hoyas grow well indoors, preferring bright light, but will tolerate fairly low light levels, although they may not flower without bright light. Hoyas commonly sold in nurseries as houseplants include cultivars of H. carnosa (Krimson Queen, Hindu Rope − compacta), H. pubicalyx (often mislabelled as H. carnosa or H. purpurea-fusca ), and H. kerrii . Hoyas are easy to propagate, and are commonly sold as cuttings, either rooted or unrooted, or as a potted plant.