The use of time units is common and necessary in everyday medical practice. Many of these units are defined and regulated by the International System of Units (SI), which is the basic language of units used worldwide since 1960 for science, technology, industry and commerce, and which was officially adopted in Colombia through Decree 2416 in 1971.

Second: (From the Latin secund-u(m)/-a(m) 'second'; documented in Spanish since 1094):

Noun

1. 1. The basic unit of time in SI which corresponds to the duration of 9,192,631,770 x 10⁹ periods of radiation from the transition between the two hyperfine levels of the ground state of the cesium-133 atom (¹³³Cs) [symbol: s]. Obs.: Up until 1967 it was defined as 1/86,400 of an average solar day. The symbols sec, and secs are incorrect.
2. 2. Noun In geometry, the traditional unit of plane angle which is the sixtieth part of an angular minute. It is each of the 60 equal parts into which a minute of circumference is divided [symbol: " ].

Medicine often uses other units of time, besides the second, which do not strictly belong to SI, such as the minute, hour, day, week, month, year and century.

Minute: (From the Latin minutu(m) 'a very small object'; documented as a unit of time in French since 1360):

Noun

1. 1. A traditional unit of time corresponding to 60 seconds or the sixtieth part of an hour [symbol: min].
2. 2. Obs.: The symbol mins is incorrect.
3. 3. Noun In geometry, it is the traditional unit of plane angle which is the sixtieth part of an angular degree. It is each of the 60 equal parts into which a degree of circumference is divided [symbol: ' ]. Synonyms: arc minute, angular minute, minute of arc.

Hour: (From the Latin hõra(m) derived from the Greek ώρα: documented in Spanish since 1129):

Noun

1. 1. A traditional unit of time corresponding to 60 minutes or, in SI, 3,600 seconds3.6 ksh Obs.: The symbols hr or hrs are incorrect.

Day: (From the Latin dies):

Noun

1. 1. A traditional unit of time, corresponding to the time it takes the earth to make a complete turn on its axis. It is equal to 24 hours or, in SI, 86,400 seconds (86.4 ks) [symbol: d].

Since these are units of measurement, their symbols should be written according to the mandatory norms, including writing them as defined (using small letters), since they are mathematic entities and not abbreviations; using the symbol rather than the unit name; separating the numeric value from the symbol with a space; and not adding a final s to indicate the plural. It is also very important not to confuse or exchange the symbols for seconds and minutes of time (s and min) with those for seconds and minutes of plane angles (" and ').

Sources:

• The International System of Units (SI) 2019. Bureau International des Poids et Mesures (Oficina Internacional de Pesos y Medidas), disponible en: www.bipm.org

• Real Academia Nacional de Medicina. Diccionario de Términos Médicos. Editorial Médica Panamericana. 2012

• Real Academia Española de la Lengua, consultado en:www.rae.es